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The aldosterone/renin ratio (ARR) is currently considered the most reliable approach for case detection of primary aldosteronism (PA). ACE (Angiotensin-converting enzyme) inhibitors are known to raise renin and lower aldosterone levels, thereby causing false-negative ARR results. Because ACE inhibitors lower angiotensin II levels, we hypothesized that the aldosterone/equilibrium angiotensin II (eqAngII) ratio (AA2R) would remain elevated in PA. Receiver operating characteristic curve analysis involving 60 patients with PA and 40 patients without PA revealed that the AA2R was not inferior to the ARR in screening for PA. When using liquid chromatography-tandem mass spectrometry to measure plasma aldosterone concentration, the predicted optimal AA2R cutoff for PA screening was 8.3 (pmol/L)/(pmol/L). We then compared the diagnostic performance of the AA2R with the ARR among 25 patients with PA administered ramipril (5 mg/day) for 2 weeks. Compared with basally, plasma levels of equilibrium angiotensin I (eqAngI) and direct renin concentration increased significantly ( P P P

Background Many medications (including most antihypertensives) and physiological factors affect the aldosterone/renin ratio (ARR) when screening for primary aldosteronism (PA). We sought to validate a novel equilibrium angiotensin II (eqAngII) assay and compare correlations between the aldosterone/angiotensin II ratio (AA2R) and the current ARR under conditions affecting the renin-angiotensin system. Methods Among 78 patients recruited, PA was excluded in 22 and confirmed in 56 by fludrocortisone suppression testing (FST). Peripheral levels of eqAngII, plasma renin activity (PRA) and direct renin concentration (DRC) were measured. Results EqAngII showed good consistency with DRC and PRA independent of PA diagnosis, posture, and fludrocortisone administration. EqAngII showed close (P Conclusions Dynamic changes of eqAngII and the AA2R show good consistency and close correlations with renin and the ARR. The eqAngII assay shows better sensitivity than DRC and PRA assays, especially at low concentrations. Whether the AA2R can reduce the impact of some factors that influence the diagnostic power of the ARR warrants further study.

Mycophenolate mofetil (MMF) or enteric coated mycophenolate sodium (EC-MPS) and steroids are used for induction and maintenance therapy in severe lupus nephritis (LN). Blood concentrations of mycophenolic acid (MPA), the active metabolite of these drugs varies among LN patients. The objective of this study was to examine whether concentration controlled (CC) dosing (via therapeutic drug monitoring) of EC-MPS result in a higher proportion of participants achieving target exposure of MPA compared to fixed dosing (FD). An additional aim of the study was to evaluate the influence of CC dosing on clinical outcomes. Nineteen participants were randomly assigned either to FD or CC group. All the participants were eligible to have free and total measurements of MPA over a period of 8-12 hours on three different occasions. Area under the concentration-time curve between 0 and 12 hours (AUC0-12) was calculated using non-compartmental method. Dose of EC-MPS was titrated according to AUC0-12 in the CC group. Thirty-two AUC0-12 measurements were obtained from 9 FD and 9 CC participants. Large interpatient variability was observed in both groups but was more pronounced in FD group. There were no significant differences between FD and CC participants in any pharmacokinetic parameters across the study visits except for total C0 (FD 2.0 ± 0.3 mg/L vs. CC 1.1 ± 0.3; p = 0.01) and dose-normalised C0 (FD 2.9 ± 0.2 mg/L/g vs. CC 2.1 ± 0.7 mg/L/g; p = 0.04) at the second visit and total AUC0-12 (FD 66.6 ± 6.0 mg[BULLET OPERATOR]h/L vs. CC 35.2 ± 11.4 mg[BULLET OPERATOR]h/L; p = 0.03) at the third visit. At the first study visit, 33.3% of the FD and 11.1% of the CC participants achieved the target AUC (p = 0.58). From the second visit, none of the FD participants, compared to all the CC participants, achieved target AUC0-12 (p = 0.01). More CC participants achieved remission compared to FD participants (absolute difference of -22.2, 95% confidence interval -0.19-0.55; p = 0.62). The mean free MPA AUC0-12 was significantly lower in those who had complete remission. CC participants reached target AUC0-12 quicker. Larger studies are required to test clinical efficacy.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Background In primary aldosteronism (PA), excessive, autonomous secretion of aldosterone is not suppressed by salt loading or fludrocortisone. For seated saline suppression testing (SSST), the recommended diagnostic cutoff 4-hour plasma aldosterone concentration (PAC) measured by high-performance liquid chromatography–mass spectrometry (HPLC-MS/MS is 162 pmol/L. Most diagnostic laboratories, however, use immunoassays to measure PAC. The cutoff for SSST using immunoassay is not known. We hypothesized that the cutoff is different between the assays. Methods We analyzed 80 of the 87 SSST tests that were performed during our recent study defining the HPLC-MS/MS cutoff. PA was confirmed in 65 by positive fludrocortisone suppression testing (FST) and/or lateralization on adrenal venous sampling and excluded in 15 by negative FST. PAC was measured by a chemiluminescence immunoassay (PACIA) in the SSST samples using the DiaSorin Liaison XL analyzer, and receiver operating characteristics (ROC) analysis was performed to identify the PACIA cutoff. Results ROC revealed good performance (area under the curve = 0.893; P < .001) of 4-hour postsaline PACIA for diagnosis of PA and an optimal diagnostic cutoff of 171 pmol/L, with sensitivity and specificity of 95.4% and 80.0%, respectively. A higher cutoff of 217 pmol/L improved specificity (86.7%) with lower sensitivity (86.2%). PACIA measurements strongly correlated with PAC measured by HPLC-MS (r = 0.94, P < .001). Conclusions A higher diagnostic cutoff for SSST should be employed when PAC is measured by immunoassay rather than HPLC-MS/MS. The results suggest that (i) PA can be excluded if 4-hour PACIA is less than 171 pmol/L, and (ii) PA is highly likely if the PACIA is greater than 217 pmol/L by chemiluminescence immunoassay. A gray zone exists between the cutoffs of 171 and 217 pmol/L, likely reflecting a lower specificity of immunoassay.

Objectives We evaluated the analytical performance characteristics and the biological equivalence of the Atellica TnIH assay. Methods Precision, detection capability, linearity, and sex specific 99th percentiles were determined de novo. Classification of patients relative to the 99th percentiles was used to assess biological equivalence. Results Analytical precision and detection capability of the Atellica TnIH assay is excellent with a limit of blank ≥±1.96) occurred in 65% (95% CI 53–76%) of 99th percentile discordant patients compared to 2.7% (p Conclusions The 99th percentile discordant and the concordantly elevated groups are more alike with respect to their z≥±1.96 rates. This favours an overestimated Atellica TnIH 99th percentile as more likely, and we hypothesize that antibody interference resulting in asymmetric scatter of nearly 5% samples may be the underlying mechanism. Analytical accuracy and interferences in cardiac troponin assays should be investigated and resolved with high priority.

IntroductionAlcohol use in patients presenting to the emergency department (ED) is a significant problem in many countries. There is a need for valid and reliable surveillance of the prevalence of alcohol use in patients presenting to the ED, to provide a more complete picture of the risk factors and inform targeted public health interventions. This PACE study will use two biomarkers, blood ethanol and phosphatidylethanol (PEth), to determine the patterns, presence and level of alcohol use in patients presenting to an Australian ED.Methods and analysisThis is an observational prevalence study involving the secondary use of routinely collected blood samples from patients presenting to the Royal Brisbane and Women’s Hospital (RBWH) Emergency and Trauma Centre (ETC). Samples will be tested for acute and medium-term alcohol intake using the two biomarkers blood ethanol and PEth respectively, over one collection period of 10–12 days. Descriptive statistics such as frequencies, percentages, means, SD, medians and IQRs, will be used to describe the prevalence, pattern and distribution of acute and medium-term alcohol intake in the study sample. The correlation between acute and medium-term alcohol intake levels will also be examined.Ethics and disseminationThis study has been approved by the RBWH Human Research Ethics Committee (reference, LNR/2019/QRBW/56859). Findings will be disseminated to key stakeholders such as RBWH ETC, Australasian College for Emergency Medicine, Royal Australasian College of Surgeons, Statewide Clinical Networks, and used to inform clinicians and hospital services. Findings will be submitted for publication in peer-reviewed journals and presentation at appropriate conferences.

Background Piperacillin-tazobactam is commonly used in neutropenic sepsis at standard doses that do not account for inter-individual differences in age, bodyweight and renal function. This study was designed to assess the rate of attainment of pharmacokinetic/pharmacodynamic (PK/PD) targets in patients receiving piperacillin/tazobactam therapy and to evaluate the effect on clinical outcomes. Methods Patients undergoing intensive chemotherapy for aggressive hematological malignancies were enrolled and treated with piperacillin/tazobactam 4 g/0.5 g every 6 h as initial antimicrobial therapy for first fever. Plasma drug concentrations were assayed at 50% and 100% of the dosing interval and compared with target MIC breakpoint of 16 mg/L to calculate the primary endpoints of 50% and 100% time above MIC (fT > MIC), respectively. Secondary endpoints included time to clinical cure, length of hospital stay, duration of antibiotics, and clinical treatment success. Results Fifty-eight percent (14/24) of patients achieved 50% fT > MIC while only 4% (1/24) achieved 100% fT > MIC. Higher creatinine clearance was significantly associated with lower trough drug concentration and appeared to be the dominant reason for the poor PK/PD target attainment. Median time to clinical cure, duration of antibiotic therapy, and hospital length of stay was 3, 13 and 21 days, respectively. There were no statistically significant differences in these outcomes between patients who did and did not achieve 100% fT > MIC. Conclusions A significant majority of febrile neutropenic patients fail to achieve PK/PD targets with 6-hourly piperacillin dosing, although the clinical implications of this finding are unclear. Larger studies are needed to assess any impact on morbidity and mortality. This trial is registered on the ANZCTR (ACTRN12618000110280).

Proximal tubular epithelial cells (PTEC) are central players in inflammatory kidney diseases. However, the complex signalling mechanism/s via which polarized PTEC mediate disease progression are poorly understood. Small extracellular vesicles (sEV), including exosomes, are recognized as fundamental components of cellular communication and signalling courtesy of their molecular cargo (lipids, microRNA, proteins). In this study, we examined the molecular content and function of sEV secreted from the apical versus basolateral surfaces of polarized human primary PTEC under inflammatory diseased conditions. PTEC were cultured under normal and inflammatory conditions on Transwell inserts to enable separate collection and isolation of apical/basolateral sEV. Significantly increased numbers of apical and basolateral sEV were secreted under inflammatory conditions compared with equivalent normal conditions. Multi‐omics analysis revealed distinct molecular profiles (lipids, microRNA, proteins) between inflammatory and normal conditions for both apical and basolateral sEV. Biological pathway analyses of significantly differentially expressed molecules associated apical inflammatory sEV with processes of cell survival and immunological disease, while basolateral inflammatory sEV were linked to pathways of immune cell trafficking and cell‐to‐cell signalling. In line with this mechanistic concept, functional assays demonstrated significantly increased production of chemokines (monocyte chemoattractant protein‐1, interleukin‐8) and immuno‐regulatory cytokine interleukin‐10 by peripheral blood mononuclear cells activated with basolateral sEV derived from inflammatory PTEC. We propose that the distinct molecular composition of sEV released from the apical versus basolateral membranes of human inflammatory PTEC may reflect specialized functional roles, with basolateral‐derived sEV pivotal in modulating tubulointerstitial inflammatory responses observed in many immune‐mediated kidney diseases. These findings provide a rationale to further evaluate these sEV‐mediated inflammatory pathways as targets for biomarker and therapeutic development.

Ivermectin is a broad-spectrum antiparasitic agent used for the treatment and control of neglected tropical diseases. In Australia, ivermectin is primarily used for scabies and is licensed in children aged ≥5 years weighing >15 kg. However, young children, aged 15 kg. Doses of 200 μg/kg rounded to the nearest whole or half 3 mg tablet were given to children with scabies and ivermectin concentrations determined at two time points after dosing. A population pharmacokinetic model was developed using non-linear mixed effects modelling. A separate covariate database of children aged 2 to 4 years and weighing 5 years. The median simulated area under the concentration-time curve was 976 μg∙h/L. Using modelling, we have identified a dosing strategy for ivermectin in children aged 2 to 4 years and weighing less than 15 kg that can be prospectively evaluated for safety and efficacy., Author summary Ivermectin is an important drug for the control and treatment of neglected tropical diseases. However, despite numerous studies showing that ivermectin is safe and well tolerated in young children, it is not currently recommended in young children

Objective: Measurement of hypertonic saline-stimulated copeptin has recently been described for the differentiation of polyuria-polydipsia syndrome. This study aims to determine the copeptin response to intravenous 3% hypertonic saline, including evaluation of adverse effects, in a local cohort of healthy adults >18 years in Australia. Design: Prospective clinical study. Methods: Twenty healthy volunteers (10 males and 10 females) were recruited. Participants underwent infusion of 3% hypertonic saline via a previously described standardized protocol, until the plasma sodium was ≥150 mmol/L, with measurement of plasma copeptin. Results: Mean peak sodium was 152 mmol/L ± SD 1.4 with osmolality 315 mmol/kg ± SD 3.9. Median volume of hypertonic saline infused to reach target sodium ≥ 150 mmol/L was 1536 mL (IQR 1362, 1992). Mean rate of plasma sodium rise was 5.9 mmol/L/hour ± SD 1.5. Hypertonic saline-stimulated copeptin had non-parametrical distribution with median of 33.8 pmol/L (IQR 27.6, 63.6). Overall median symptom burden was 6/10 (range 3/10-9/10). Copeptin was significantly higher for those who experienced nausea and/or vomiting (n = 13) (median 39.0 pmol/L; IQR 32.5, 90), compared to those participants who did not experience either (median 20.0 pmol/L; IQR 13.0, 31.0) (P = 0.003). There were no serious adverse events. Conclusion: Hypertonic saline-stimulated copeptin measurements were similar in our population compared with previously reported reference intervals in healthy volunteers. There is a wide range of stimulated copeptin measurements in the healthy population. Nausea and vomiting are common adverse effects which enhance the copeptin response.

A survey of kidney transplant recipients receiving two innovative microsampling methods, dried blood spot and volumetric absorptive microsampling using patient reported methodology. A total of 39 adult transplant patients underwent venepuncture and finger prick-based blood draws on two occasions. They completed a survey of blood test understanding, tolerability, preferences and the burden associated with venepuncture compared with microsampling. A total of 85% of participants (n = 33) preferred finger prick-based sampling and 95% (n = 37) were interested in blood collection using self sampling by finger prick at home; 33% (n = 13) of participants experienced blood test anxiety. To quantify time burden of providing venous samples a total of 44% (n = 17) spent greater than 1 hour to travel and provide venous samples. This study observed a patient preference for microsampling for blood sampling as an alternative to venepuncture in the management of their kidney transplant.

Context and Objective Posture-responsive and posture-unresponsive aldosterone-producing adenomas (APAs) account for approximately 40% and 60% of APAs, respectively. Somatic gene mutations have been recently reported to exist in approximately 90% of APAs. This study was designed to characterize the biochemical, histopathologic, and genetic properties of these 2 types of APA. Methods Plasma levels of aldosterone and hybrid steroids (18-oxocortisol and 18-hydroxycortisol) were measured by liquid chromatography-tandem mass spectrometry. Immunohistochemistry for CYP11B2 (aldosterone synthase) and CYP17A1 (17α-hydroxylase) and deoxyribonucleic acid sequencing (Sanger and next-generation sequencing) were performed on APA tissue collected from 23 posture-unresponsive and 17 posture-responsive APA patients. Results Patients with posture-unresponsive APA displayed higher (P < 0.01) levels of hybrid steroids, recumbent aldosterone and cortisol, larger (P < 0.01) zona fasciculata (ZF)-like tumors with higher (P < 0.01) expression of CYP17A1 (but not of CYP11B2) than patients with posture-responsive APA (most of which were not ZF-like). Of 40 studied APAs, 37 (92.5%) were found to harbor aldosterone-driving somatic mutations (KCNJ5 = 14 [35.0%], CACNA1D = 13 [32.5%], ATP1A1 = 8 [20.0%], and ATP2B3 = 2 [5.0%]), including 5 previously unreported mutations (3 in CACNA1D and 2 in ATP1A1). Notably, 64.7% (11/17) of posture-responsive APAs carried CACNA1D mutations, whereas 56.5% (13/23) of posture-unresponsive APAs harbored KCNJ5 mutations. Conclusions The elevated production of hybrid steroids by posture-unresponsive APAs may relate to their ZF-like tumor cell composition, resulting in expression of CYP17A1 (in addition to somatic gene mutation-driven CYP11B2 expression), thereby allowing production of cortisol, which acts as the substrate for CYP11B2-generated hybrid steroids.

Context Current threshold values for primary aldosteronism (PA) diagnostic testing are based on measuring aldosterone (PAC) using immunoassays. Quantification of PAC by liquid chromatography-tandem mass spectrometry (LC-MS/MS) yields lower values. Objective To compare aldosterone measurement by radioimmunoassay (RIA) with LC-MS/MS and evaluate performances of proposed LC-MS/MS–specific cutoffs for PA screening and confirmatory testing. Patients and Intervention Forty-one patients underwent aldosterone/renin ratio (ARR) testing to screen for, and fludrocortisone suppression testing (FST) to confirm or exclude, PA. Renin (DRC) was measured by chemiluminescent immunoassay. Results Median serum PACLC-MS/MS was 27.8% lower (P < 0.05) than plasma PACRIA in 164 pairs of FST samples. A positive correlation (Spearman coefficient, 0.894, P < 0.01; Pearson r coefficient, 0.861, P < 0.01) was observed between the two assays. Thirty-seven patients showed consistent FST diagnoses (29 positive, 8 negative), whereas four showed inconsistent FSTs by the two assays. Good agreement (κ coefficient, 0.736; P < 0.01) was observed between the current FST diagnostic PACRIA cutoff of 165 pmol/L and the proposed PACLC-MS/MS cutoff of 133 pmol/L. Among 37 patients with consistent FST results, no differences were observed in sensitivity (89.7% vs 93.1%) or specificity (87.5% vs 87.5%) for PA screening between the current ARR cutoff of 70 pmol/mU (PACRIA/DRC) and the proposed cutoff of 55 pmol/mU (PACLC-MS/MS/DRC). Conclusions Adjustment of the current cutoffs for PA diagnostic testing is necessary if PAC is measured by LC-MS/MS. Our preliminary results suggest that the proposed LC-MS/MS cutoffs for ARR and FST perform as well as current RIA cutoffs.

BACKGROUND Low concentrations of cardiac troponin (cTn) have been recommended for rapid rule-out of acute myocardial infarction (AMI). We examined the Beckman Coulter Access high-sensitivity cardiac troponin I (hs-cTnI) assay to identify a single test threshold that can safely rule out AMI. METHODS This analysis used stored samples collected in 2 prospective observational studies. In all, 1871 patients presenting to a tertiary emergency department with symptoms of acute coronary syndrome had blood taken for measurement of cTnI on presentation. The endpoint was type 1 myocardial infarction (T1MI). Sensitivity and negative predictive value (NPV) were calculated for hs-cTnI values below the 99th percentile. RESULTS Ninety-eight patients had T1MI (5.2%), and 638 (34.1%) patients had an hs-cTnI CONCLUSIONS A single baseline cTn

Introduction We investigated the analytical performance, outlier rate, carryover and reference interval of the Beckman Coulter Access hsTnI in detail and compared it with historical and other commercial assays. Materials and methods We compared the imprecision, detection capability, analytical sensitivity, outlier rate and carryover against two previous Access AccuTnI assay versions. We established the reference interval with stored samples from a previous study and compared the concordances and variances with the Access AccuTnI+3 as well as with two commercial assays. Results The Access hsTnI had excellent analytical sensitivity with the calibration slope 5.6 times steeper than the Access AccuTnI+3. The detection capability was markedly improved with the SD of the blank 0.18–0.20 ng/L, LoB 0.29–0.33 ng/L and LoD 0.58–0.69 ng/L. All the reference interval samples had a result above the LoB value. At a mean concentration of 2.83 ng/L the SD was 0.28 ng/L (CV 9.8%). Carryover (0.005%) and outlier (0.046%) rates were similar to the Access AccuTnI+3. The combined male and female 99th percentile reference interval was 18.2 ng/L (90% CI 13.2–21.1 ng/L). Concordance amongst the assays was poor with only 16.7%, 19.6% and 15.2% of samples identified by all 4 assays as above the 99th, 97.5th and 95th percentiles. Analytical imprecision was a minor contributor to the observed variances between assays. Conclusion The Beckman Coulter Access hsTnI assay has excellent analytical sensitivity and precision characteristics close to zero. This allows cTnI measurement in all healthy individuals and the capability to identify numerically small differences between serial samples as statistically significant. Concordance in healthy individuals remains poor amongst assays.

Background: Plasma aldosterone/renin ratio (ARR) is the most popular screening test for primary aldosteronism (PA). Because both estrogen and progesterone (including in oral contraceptive agents) affect aldosterone and renin levels, we studied the effects of combined hormonal replacement therapy (HRT) on ARR; renin was measured as both direct renin concentration (DRC) and plasma renin activity (PRA). Methods: Fifteen normotensive, healthy postmenopausal women underwent measurement (seated, midmorning) of plasma aldosterone, DRC, PRA, electrolytes, and creatinine and urinary aldosterone, cortisol, electrolytes, and creatinine at baseline and after 2 weeks and 6 weeks of treatment with combined HRT (conjugated estrogens 0.625 mg and medroxyprogesterone 2.5 mg daily). Results: Combined HRT was associated with statistically significant increases in aldosterone [median (range): baseline, 150 (85 to 600); 2 weeks, 230 (129 to 790); 6 weeks, 434 (200 to 1200) pmol/L; P < 0.001 (Friedman test)] and PRA [2.3 (1.2 to 4.3), 3.8 (1.4 to 7.0), 5.1 (1.4 to 10.8) ng/mL/h, respectively; P < 0.001] but decreases in DRC [21 (10 to 31), 21 (10 to 39), and 14 (8.0 to 30) mU/L, respectively; P < 0.01], leading to increases in ARR calculated by DRC [7.8 (3.6 to 34.8), 11.4 (5.4 to 48.5), and 30.4 (10.5 to 90.2), respectively; P < 0.001]. The ARR calculated by DRC exceeded the cutoff value (70) in three patients after 6 weeks. There were no significant changes in ARR calculated by PRA [79 (26 to 184), 91 (23 to 166), and 88 (50 to 230), respectively; P = 0.282], plasma electrolytes and creatinine, or any urinary measurements. Conclusion: The combined oral HRT used in this study is capable of significantly increasing ARR with a risk of false-positive results during screening for PA but only if DRC (and not PRA) is used to calculate the ratio.

ObjectiveTo evaluate the role of fasting blood glucose (FBG) to minimise the use of the oral glucose tolerance test in pregnancy (POGTT) for the diagnosis of gestational diabetes mellitus (GDM).Research design and methodsWe analysed the POGTTs of 26,242 pregnant women in Queensland, Australia, performed between 1 January 2015 and 30 June 2015. A receiver operator characteristics (ROC) assessment was undertaken to indicate the FBG level that most effectively identified women at low risk of an abnormal result.ResultsThere were 3,946 (15.0%) patients having GDM with 2,262 (8.6%) having FBG ≥ 5.1mmol/l. The ROC identified FBG levels >4.6mmol/l having the best specificity (77%) and sensitivity (54%) for elevated 1 and/or 2hr BGLs. There were 19,321 (73.7%) women having FBG < 4.7mmol/l with a prevalence of GDM of 4.0%, less than 1/3rdthe overall rate. Only 4,638 (17.7%) women having FBGs from 4.7–5.0mmol/l would require further evaluation to confirm or exclude the diagnosis.ConclusionThis contemporary study of women across the state of Queensland, Australia suggests the FBG can be used effectively to define glucose tolerance in pregnancy, minimising their contact with pathology laboratories and potential exposure to the corona virus. This analysis, used in conjunction with outcome data from the HAPO study, provides reassurance to women and their health professionals that FBG < 4.7mmol/l has both a low rate of abnormal glucose tolerance and minimal adverse pregnancy-associated complications.

BACKGROUND We compared the 99th percentile reference intervals with 3 modern cardiac troponin assays in a single cohort and tested the hypothesis that the same individuals will be identified as above the cutoff and that differences will be explained by analytical imprecision. METHODS Blood was collected from 2005 apparently healthy blood donors. Cardiac troponin was measured with Abbott Architect STAT high sensitive troponin I, Beckman Coulter Access AccuTnI+3, and Roche Elecsys troponin T highly sensitive assays. RESULTS The 99th percentile cutoff limits were as follows: Abbott cardiac troponin I (cTnI) 28.9 ng/L; Beckman Coulter cTnI 31.3 ng/L; and Roche cardiac troponin T (cTnT) 15.9 ng/L. Correlation among the assays was poor: Abbott cTnI vs Beckman Coulter cTnI, R2 = 0.18; Abbott cTnI vs Roche cTnT, R2 = 0.04; and Beckman Coulter cTnI vs Roche cTnT R2 = 0.01. Of the results above the cutoff 50% to 70% were unique to individual assays, with only 4 out of 20 individuals above the cutoff for all 3 assays. The observed differences among assays were larger than predicted from analytical imprecision. CONCLUSIONS The 99th percentile cutoff values were in agreement with those reported elsewhere. The poor correlation and concordance amongst the assays were notable. The differences found could not be explained by analytical imprecision and indicate the presence of inaccuracy (bias) that is unique to sample and assay combinations. Based on these findings we recommend less emphasis on the cutoff value and greater emphasis on δ values in the diagnosis of myocardial infarction.

Background: Prolonged intermittent renal replacement therapy (PIRRT) eliminates many drugs, and without dosing data, for new antibiotics like ceftolozane/tazobactam, suboptimal concentrations and treatment failure are likely. Objectives: Herein, we describe the effect of PIRRT on the plasma pharmacokinetics of ceftolozane/tazobactam ad­ministered in a critically ill 55-year-old patient with a polymicrobial sternal wound osteomyelitis, including a multiresistant Pseudomonas aeruginosa. Method: Blood samples were taken over 4 days where the patient received a 7.5-h PIRRT treatment. One- and 2-compartment models were tested for ceftolozane and tazobactam separately, and the log-likelihood ratio and goodness-of-fit plots were used to select the final model. Results: Two-compartment models were developed for ceftolozane and tazobactam separately and described significant differences in clearance of ceftolozane and tazobactam with and without PIRRT (8.273 vs. 0.393 and 8.020 vs. 0.767 L/h, respectively). Conclusions: A ceftolozane/tazobactam dose of 500 mg/250 mg appears to be sufficient to attain pharmacokinetic/pharmacodynamic targets during PIRRT while the manufacturer’s recommended dosing of 100 mg/50 mg every 8 h was sufficient during non-PIRRT periods.

Failure of plasma aldosterone suppression during fludrocortisone suppression testing (FST) or saline suppression testing (SST) confirms primary aldosteronism (PA). Aldosterone is often higher upright than recumbent in PA; upright levels are used during FST. In a pilot study (24 patients with PA), seated saline suppression testing (SSST) was more sensitive than recumbent saline suppression testing (RSST).The current validation study involved 100 patients who underwent FST, RSST, and SSST, eight before and after unilateral adrenalectomy. Of the 108 FSTs, 73 confirmed and 18 excluded PA. Four patients with inconclusive FST lateralized on adrenal venous sampling, making a total of 77 with PA.The area under the receiver operating characteristic (ROC) curve was greater for SSST than RSST (0.96 vs. 0.80; P0.01). ROC analysis predicted optimal cutoff aldosterone levels of 162 pmol/L for SSST and 106 pmol/L for RSST. At these cutoffs, SSST showed high sensitivity for PA (87%) that markedly exceeded that for RSST (38%; P0.001) but similar specificity (94 vs. 94%; not significant). SSST was more sensitive than RSST in detecting both unilateral (n = 28, 93% vs. 68%, P0.05) and bilateral (n = 40, 85% vs. 20%, P0.001) forms of PA. Only three SSST (vs. 9 RSST and 17 FST) results were inconclusive.SSST is highly sensitive and superior to RSST in identifying both unilateral and bilateral forms of PA and has a low rate of false positives and inconclusive results. It therefore offers a reliable and much less complicated and expensive alternative to FST for confirming PA.

To describe the achievement of unbound β-lactam antibiotic concentration targets in a therapeutic drug monitoring (TDM) programme in critically ill patients, and the factors associated with failure to achieve a target concentration.Plasma samples and clinical data were obtained for analysis from a single centre prospectively. Unbound concentrations of ceftriaxone, cefazolin, meropenem, ampicillin, benzylpenicillin, flucloxacillin and piperacillin were directly measured using ultracentrifugation. Factors associated with the achievement of pharmacokinetic/pharmacodynamic (PK/PD) targets or negative clinical outcomes were evaluated with binomial logistic regression.TDM data from 330 patients, and 369 infection episodes, were included. The range of doses administered was 99.4% ± 45.1% relative to a standard daily dose. Dose increases were indicated in 33.1% and 63.4% of cases to achieve PK/PD targets of 100% fTMIC and 100% fT4×MIC, respectively. Dose reduction was indicated in 17.3% of cases for an upper PK/PD threshold of 100% fT10×MIC. Higher protein bound β-lactams (ceftriaxone and benzylpenicillin) had better therapeutic target attainment (P 0.01), but were prone to excessive dosing. Augmented renal clearance (calculated CLCR130 mL/min) increased the odds of failure to achieve 100% fTMIC and 100% fT4×MIC (OR 2.47 and 3.05, respectively; P 0.01).Measuring unbound concentrations of β-lactams as part of a routine TDM programme is feasible and demonstrates that a large number of critically ill patients do not achieve predefined PK/PD targets. The clinical significance of this finding is unknown due to the lack of correlation between PK/PD findings and clinical outcomes.

A 35-year-old patient in intensive care with severe burn injury developed episodes of sepsis. Blood culture yielded a multidrug-resistant Pseudomonas aeruginosa and treatment was commenced with amikacin (minimum inhibitory concentration (MIC) 2-4 mg/L, dose 20 mg/kg adjusted body weight 24-hourly) and meropenem (MIC 8 mg/L, dose 2 g IV 8-hourly and later 6-hourly). Despite the use of extended infusions with β-lactam therapeutic drug monitoring and doses that were more than 2.5 times higher than standard meropenem doses, resistance emerged. This case report describes the application of therapeutic drug monitoring to optimize β-lactam therapy in a difficult-to-treat critically ill patient.

There is increasing need to identify individuals with advanced liver fibrosis, who are at risk of complications such as hepatocellular carcinoma. The commercially available enhanced liver fibrosis (ELF) test provides a non-invasive assessment of fibrosis severity. This study was designed to determine the diagnostic accuracy of the manufacturer's cut-off value (≥9.8) in identifying advanced fibrosis.The relationship between ELF score and fibrosis was examined using serum collected at time of liver biopsy for investigation of liver disease, particularly viral hepatitis. Fibrosis was staged using a modified METAVIR score. If available, liver tissue was recut and stained with Sirius red to determine collagen proportional area (CPA) and subsinusoidal fibrosis (SSF).Enhanced liver fibrosis score ≥9.8 had a sensitivity of 74.4% and specificity 92.4% for detecting advanced fibrosis. In the whole cohort (n = 329), ELF score was more likely to incorrectly classify individuals if age was ≥45 years and METAVIR inflammatory grade was 2 or 3 (adjusted OR, odds ratio 3.71 and 2.62 respectively). In contrast, ELF score was less likely to misclassify individuals in the presence of steatosis (OR 0.37). Neither SSF nor CPA explained the discordance in ELF score for patients with or without advanced fibrosis.Although ELF score ≥9.8 reliably identifies advanced fibrosis in patients with chronic liver disease, both age and inflammatory activity need to be considered when interpreting the result. Importantly, ELF score performed well in the presence of steatosis and could thus be helpful in the assessment of fatty liver disease.

Background Measured (MO) and calculated osmotic concentrations (CO) and the osmotic gap (OG) are commonly used in the investigation of electrolyte and volume disturbances as well as in cases of suspected volatile ingestion. Methods We compared 38 published formulae for CO with MO on a large data-set ( n = 9466) and adjusted the CO with the result of a Passing-Bablok regression procedure. Validation of this adjustment was performed with a separate data-set ( n = 2082). Results All but one of the CO formulae underestimate MO due to a proportional bias (slope 0.67 to 0.95) and the OG limits were therefore not applicable throughout the observed range. Using Passing-Bablok regression to adjust the CO: CO#3 = (2 × Na+urea+glucose−14.54)/0.93. After adjustment, the mean OG was 0.3 mmol/L with a SD of 5.1 mmol/L across the measurement interval. The distribution of the OG could be fully explained by the analytical imprecision of the measured components. Conclusions Simple adjustment of the CO for the proportional underestimation of MO allows OG reference limits of approximately −10 to +10 mmol/L to be used, even in the upper ranges of CO in patients with suspected volatile ingestion.

Burns and their associated wound care procedures evoke significant stress and anxiety, particularly for children. Little is known about the body's physiological stress reactions throughout the stages of re-epithelialization following an acute burn injury. Previously, serum and urinary cortisol have been used to measure stress in burn patients, however these measures are not suitable for a pediatric burn outpatient setting.To assess the sensitivity of salivary cortisol and sAA in detecting stress during acute burn wound care procedures and to investigate the body's physiological stress reactions throughout burn re-epithelialization.Seventy-seven participants aged four to thirteen years who presented with an acute burn injury to the burn center at the Royal Children's Hospital, Brisbane, Australia, were recruited between August 2011 and August 2012.Both biomarkers were responsive to the stress of burn wound care procedures. sAA levels were on average 50.2 U/ml higher (p0.001) at 10 min post-dressing removal compared to baseline levels. Salivary cortisol levels showed a blunted effect with average levels at ten minutes post dressing removal decreasing by 0.54 nmol/L (p0.001) compared to baseline levels. sAA levels were associated with pain (p=0.021), no medication (p=0.047) and Child Trauma Screening Questionnaire scores at three months post re-epithelialization (p=0.008). Similarly, salivary cortisol was associated with no medication (p0.001), pain scores (p=0.045) and total body surface area of the burn (p=0.010).Factors which support the use of sAA over salivary cortisol to assess stress during morning acute burn wound care procedures include; sensitivity, morning clinic times relative to cortisol's diurnal peaks, and relative cost.

Aims: We assessed the diagnostic performance of z-scores to define a significant delta cardiac troponin (cTn) in a cohort of patients with well-defined clinical outcomes. Methods: We calculated z-scores, which are dependent on the analytical precision and biological variation, to report changes in cTn. We compared the diagnostic performances of a relative delta (%Δ), actual delta (Δ), and z-scores in 762 emergency department patients with symptoms of suspected acute coronary syndrome. cTn was measured with sensitive cTnI (Beckman Coulter), highly sensitive cTnI (Abbott), and highly sensitive cTnT (Roche) assays. Results: Receiver operating characteristic analysis showed no statistically significant differences in the areas under the curve (AUC) of z-scores and Δ with both superior compared to %Δ for all three assays (p

Objectives: The objective of this study was to characterize cefazolin serum pharmacokinetics in children before, during and after cardiopulmonary bypass (CPB), in order to derive an evidence-based dosing regimen. Patients and methods: This study included children who received cefazolin before surgical incision, before cessation of CPB and after surgery. Blood samples of total and unbound cefazolin concentrations were collected before, during and after CPB. The cefazolin concentration-time profiles were analysed using population pharma-cokinetic modelling and predictors for interindividual variability in pharmacokinetic parameters were investigated. Subsequently, optimized dosing regimens were developed using stochastic simulations. Clinicaltrials. gov: NCT02749981. Results: A total of 494 total and unbound cefazolin concentrations obtained from 56 children (aged 6 days to 15 years) were included. A two-compartment model with first-order elimination plus an additional compartment for the effect of CPB best described the data. Clearance (1.56 L/h), central volume (1.93 L) and peripheral volume (2.39 L) were allometrically scaled by body weight. The estimated glomerular filtration rate(eGFR) was identified as a covariate on clearance and the serum albumin concentration was associated with maximum protein binding capacity. Our simulations showed that an additional bolus dose at the start of CPB improves the PTA in typical patients from 59% to >94%. Prolonged surgery and preserved renal function (i.e. drop in eGFR < 25%) had a negative impact on PTA. Conclusions: We propose an optimized dosing regimen for cefazolin during cardiac surgery in paediatric patients to avoid treatment failure due to inadequate antibiotic prophylaxis.

Omega-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory properties, whereas omega-6 PUFAs appear to have proinflammatory properties. We aimed to assess plasma omega-3 and omega-6 PUFA status in relation to all-cause mortality in an Australian community-based study. We hypothesized that omega-3 PUFA would be inversely associated, and omega-6 PUFA positively associated with all-cause mortality. Plasma phospholipid omega-3 (eicosapentaenoic acid [EPA], docosapentaenoic acid [DPA], docosahexaenoic acid, α-linolenic acid, and total) and omega-6 PUFAs (linoleic acid, arachidonic acid, and total) were measured among 1008 adults (44% men) in 1996. Plasma PUFA composition was quantified using gas chromatography. During 17-year follow-up, 98 men and 81 women died. After adjustment for potential confounding factors, plasma EPA was inversely associated with all-cause mortality overall (adjusted hazard ratio [HR] per 1-SD increase, 0.81; 95% confidence interval [CI], 0.68-0.95), in men (HR, 0.78; 95% CI, 0.62-0.98), and in women (HR, 0.78; 95% CI, 0.65-0.94), separately. Inverse associations with mortality among men were also seen for DPA (HR, 0.76; 95% CI, 0.60-0.97) and α-linolenic acid (HR, 0.73; 95% CI, 0.57-0.94). No omega-6 PUFAs were significantly associated with mortality. Our findings of reduced all-cause mortality in men and women who have high EPA in plasma, and in men with high plasma DPA and α-linolenic acid, partially support our hypothesis that omega-3 PUFAs help reduce mortality but provide no evidence that omega-6 PUFAs may increase mortality.

To measure tissue glucocorticoid sensitivity in patients with septic shock and determine its relationship to standard measurements of adrenal function and of outcome.Prospective observational trial.Teaching hospital ICU.Forty-one patients and 20 controls were studied.Glucocorticoid sensitivity was measured by in vitro suppression of cytokine production from lipopolysaccharide-stimulated leukocytes.There was no significant difference between the groups in the relative suppression of cytokine production, although there was a greater range and variance in the patient data. Patients in the lowest quartile of glucocorticoid sensitivity had higher Acute Physiology and Chronic Health Evaluation II scores (25 [24-28] vs 20 [14-23]; p = 0.02) and a trend toward higher mortality (30% vs 0%; p = 0.2) compared to those in the highest. The mRNA expression of the β variant of the glucocorticoid receptor and the 11-β hydroxysteroid dehydrogenase 2 isozyme were significantly higher in patients compared to controls (8.6-fold, p = 0.002 and 10.1-fold, p = 0.0002, respectively). Changes in mRNA expression of these genes did not correlate with measurements of glucocorticoid sensitivity.Patients with septic shock and controls do not differ in their median glucocorticoid sensitivity. However, patients exhibited a greater variability in glucocorticoid responsiveness and had evidence of association between increased sickness sensitivity and reduced glucocorticoid sensitivity. Sensitivity to glucocorticoids did not appear to be mediated by changes in the expression of the β variant of the glucocorticoid receptor or the 11-β hydroxysteroid dehydrogenase 2 isozyme.

Background and objectives The generation of key uremic nephrovascular toxins, indoxyl sulfate (IS), and p-cresyl sulfate (PCS), is attributed to the dysbiotic gut microbiota in CKD. The aim of our study was to evaluate whether synbiotic (pre- and probiotic) therapy alters the gut microbiota and reduces serum concentrations of microbiome–generated uremic toxins, IS and PCS, in patients with CKD. Design, setting, participants, & measurements Predialysis adult participants with CKD (eGFR=10–30 ml/min per 1.73 m2) were recruited between January 5, 2013 and November 12, 2013 to a randomized, double–blind, placebo–controlled, crossover trial of synbiotic therapy over 6 weeks (4-week washout). The primary outcome was serum IS. Secondary outcomes included serum PCS, stool microbiota profile, eGFR, proteinuria-albuminuria, urinary kidney injury molecule-1, serum inflammatory biomarkers (IL-1β, IL-6, IL-10, and TNF-α), serum oxidative stress biomarkers (F2-isoprostanes and glutathione peroxidase), serum LPS, patient-reported health, Gastrointestinal Symptom Score, and dietary intake. A prespecified subgroup analysis explored the effect of antibiotic use on treatment effect. Results Of 37 individuals randomized (age =69±10 years old; 57% men; eGFR=24±8 ml/min per 1.73 m2), 31 completed the study. Synbiotic therapy did not significantly reduce serum IS (−2 μmol/L; 95% confidence interval [95% CI], −5 to 1 μmol/L) but did significantly reduce serum PCS (−14 μmol/L; 95% CI, −27 to −2 μmol/L). Decreases in both PCS and IS concentrations were more pronounced in patients who did not receive antibiotics during the study (n=21; serum PCS, −25 μmol/L; 95% CI, −38 to −12 μmol/L; serum IS, −5 μmol/L; 95% CI, −8 to −1 μmol/L). Synbiotics also altered the stool microbiome, particularly with enrichment of Bifidobacterium and depletion of Ruminococcaceae. Except for an increase in albuminuria of 38 mg/24 h (P=0.03) in the synbiotic arm, no changes were observed in the other secondary outcomes. Conclusion In patients with CKD, synbiotics did not significantly reduce serum IS but did decrease serum PCS and favorably modified the stool microbiome. Large–scale clinical trials are justified.

Background: Beta-lactams are first-line antibiotics for the management of superficial infections due to burn injury. There is sparse data available on therapeutic drug monitoring (TDM) in patients with burns in a ward setting. This study was conducted to evaluate the utility of a beta-lactam TDM program in a cohort of burn injury patients in a ward environment. Methods: Steady-state blood samples were collected immediately before a scheduled dose. The therapeutic concentration targets assessed were (1) free antibiotic concentrations exceeding the minimum inhibitory concentration (MIC; fT > MIC) and (2) free concentrations =4נMIC of the known or suspected pathogen (fT > 4נMIC). The duration of therapy was also assessed. Results: A total of 50 patients were included for TDM over a 12-month period. The mean (ᓄ) age was 49 ᠱ6 years. The mean percent total body surface area burn was 17 ᠱ3%. The mean serum creatinine concentration was 86 ᠲ0 孯le/L. Sixty percent of the patients did not achieve fT > MIC, and only 18% achieved the higher target of fT > 4נMIC. Although all the patients achieved a positive clinical outcome, the duration of antibiotic treatment was shorter in patients who achieved fT > MIC compared with those who did not (4.2 ᠱ.1 versus 5.3 ᠲ.3 days; P = 0.03). Conclusions: We found TDM to be a reliable intervention for burn injury patients in a ward environment. This study supports pharmacokinetic data that burns patients may be at risk of subtherapeutic dosing, which may prolong the duration of antibiotic therapy.

Published data on adrenocortical function in septic shock have enrolled patients at various stages of critical illness and predominantly used plasma total cortisol, with minimal information on serial changes. Moreover, plasma free cortisol and tissue corticosteroid activity may not be strongly associated; however, few published data exist. The aim of this prospective observational study was to investigate serial changes in plasma total and free cortisol and tissue cortisol activity in septic shock. Twenty-nine adult patients admitted with septic shock to a tertiary-level intensive care unit were enrolled. A low-dose corticotropin test was performed on day 1. Plasma total and free cortisol, cortisone, transcortin, and urinary free cortisol and cortisone were analyzed on days 1 to 5, 7, and 10. Urinary and plasma cortisol-cortisone ratios (F:E ratio) were calculated as indices of 11-β hydroxysteroid dehydrogenase 2 and global 11-β hydroxysteroid dehydrogenase activity, respectively. Baseline total and free plasma cortisol values from 10 healthy control subjects were obtained for comparative analysis. Baseline plasma total and free cortisol levels were significantly higher than controls (457.8 ± 193 vs. 252 ± 66 nmol/L, P = 0.0002; and 50.83 ± 43.19 vs. 6.4 ± 3.2, P < 0.0001, respectively). Plasma free cortisol rose proportionately higher than total cortisol (124% ± 217.3% vs. 40% ± 33.2%, P = 0.007) following corticotropin. Baseline plasma and urinary F:E ratios were elevated over the reference ranges (13.13 ± 1.5, 1.69 ± 2.8) and were not correlated with plasma free cortisol values (r = 0.2, 0.3 respectively). Over the study period, total cortisol levels and plasma F:E ratios remained elevated, whereas plasma free cortisol levels and urinary F:E ratio declined. At baseline, plasma free cortisol levels were higher in patients who subsequently survived (23.7 ± 10.5 vs. 57.9 ± 45.8 nmol/L, P = 0.04). In septic shock, there is a differential response of plasma total and free cortisol over time and in response to corticotropin. Changes in plasma and urinary F:E ratios suggest tissue modulation of 11-β hydroxysteroid dehydrogenase activity. Total plasma cortisol measurements may not reflect the global adrenal response in septic shock.

Point-of-care testing for β-hCG has been widely advocated to allow rapid diagnosis/exclusion of pregnancy in the emergency department. A quantitative blood β-hCG assay has the additional benefit of being able to monitor the viability of pregnancy, using serial measurements, to determine the appropriate expected increase in β-hCG levels over time (e.g. ectopic pregnancy), and aiding in determining if an intrauterine gestational sac should be visible on sonographic imaging. Objectives Evaluation of the newly released Abbott i-STAT β-hCG point-of-care assay with the Beckman Coulter β-hCG laboratory assay in use. Design and methods Whole blood, plasma and serum samples with a wide range of β-hCG concentrations were analysed by both methods. Results The Abbott I-STAT β-hCG compares favourably, can be performed on heparinised whole blood, plasma and serum, and shows acceptable accuracy and precision. However a hook effect at elevated β-hCG was shown in gestational trophoblastic disease as well as normal pregnancies. Conclusions The i-STAT β-hCG performs acceptably in its intended use in the early detection of pregnancy, but results should always be interpreted within the clinical context, as a hook effect may occur.

We describe an ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC MS/MS) method suitable for a routine laboratory to determine endogenous and exogenous glucocorticoids in plasma, plasma ultrafiltrate, urine and saliva in a single analytical run. After addition of a multi-analyte internal standard, a standardised sample preparation procedure with solid phase extraction followed, before injecting into a tandem mass spectrometer with positive mode electron spray ionisation and multiple reactant monitoring acquisition. The chromatography time was 3min. The limit of quantitation for cortisol and cortisone in plasma was 3.75nmol/L and linearity extended to 2000nmol/L. The limit of quantitation for cortisol in plasma ultrafiltrate and saliva was 0.6nmol/L. The limit of quantitation for 11-deoxycortisol and prednisolone was 5nmol/L and for dexamethasone 1nmol/L. The intra-assay CV was

The extreme pharmacokinetic behaviour of drugs sometimes observed in critically ill patients poses a significant threat to the achievement of optimal antibiotic treatment outcomes. Scant information on beta-lactam antibiotic therapeutic drug monitoring (TDM) is available. The objective of this prospective study was to evaluate the practicality and utility of a beta-lactam TDM programme in critically ill patients. TDM was performed twice weekly on all eligible patients at a 30-bed tertiary referral critical care unit. Blood concentrations were determined by fast-throughput high-performance liquid chromatography (HPLC) assays and were available within 12h of sampling. Dose adjustment was instituted if the trough or steady-state blood concentration was below 4-5x the minimum inhibitory concentration (MIC) or above 10x MIC. A total of 236 patients were subject to TDM over an 11-month period. The mean+/-standard deviation age was 53.5+/-18.3 years. Dose adjustment was required in 175 (74.2%) of the patients, with 119 of these patients (50.4%) requiring dose increases after the first TDM. For outcome of therapy, 206 (87.3%) courses resulted in a positive treatment outcome and there were 30 (12.7%) treatment failures observed including 14 deaths and 15 courses requiring escalation to broader-spectrum agents; 1 course was ceased due to an adverse drug reaction. Using binomial logistic regression, only an elevated Acute Physiology and Chronic Health Evaluation (APACHE) II score (P

Glucocorticoid resistance due to mutations of the glucocorticoid receptor (NR3C1) are rare, but reduced glucocorticoid sensitivity may play a role in steroid-resistant asthma, inflammatory bowel disease, and septic shock. A rapid and sensitive functional assay to detect glucocorticoid resistance will be advantageous.We describe a rapid in vitro monocyte dexamethasone suppression of cytokine production (DSCP) assay with a 3-h incubation. The DSCP assay was compared with the reference stimulated lymphocyte proliferation method. We characterized the effect of delayed processing, time of sampling, and biological variation on the DSCP assay.The DSCP assay clearly distinguished subjects with a known heterozygous mutation of the NR3C1 gene from control subjects, whereas the reference method failed. Decreased glucocorticoid sensitivity was demonstrated in samples collected in the afternoon. Intra-individual variation from samples collected in the morning was 13.0 and 12.7% for the IL-6 and TNF-alpha responses with the respective inter-individual variations of 9.7 and 7.9%.The DSCP assay was superior to the reference method and was sufficiently sensitive to detect diurnal variation in control subjects. The biological variation data supported the use of a population-based reference interval. The assay is suitable for screening of glucocorticoid resistance phenotypes and may provide insight into cortisol metabolism in critically ill patients, asthmatics, and patients with inflammatory bowel disease provided that the variation due to delayed processing and time of collection are considered.

Study objective This diagnostic accuracy study describes the performance of 5 accelerated chest pain pathways, calculated with the new Beckman's Access high-sensitivity troponin I assay. Methods High-sensitivity troponin I was measured with presentation and 2-hour blood samples in 1,811 patients who presented to an emergency department (ED) in Australia. Patients were classified as being at low risk according to 5 rules: modified accelerated diagnostic protocol to assess patients with chest pain symptoms using troponin as the only biomarker (m-ADAPT), the Emergency Department Assessment of Chest Pain Score (EDACS) pathway, the History, ECG, Age, Risk Factors, and Troponin (HEART) pathway, the No Objective Testing Rule, and the new Vancouver Chest Pain Rule. Endpoints were 30-day acute myocardial infarction and acute coronary syndrome. Measures of diagnostic accuracy for each rule were calculated. Results Data included 96 patients (5.3%) with acute myocardial infarction and 139 (7.7%) with acute coronary syndrome. The new Vancouver Chest Pain Rule and No Objective Testing Rule had high sensitivity for acute myocardial infarction (100%; 95% confidence interval [CI] 96.2% to 100% for both) and acute coronary syndrome (98.6% [95% CI 94.9% to 99.8%] and 99.3% [95% CI 96.1% to 100%]). The m-ADAPT, EDACS, and HEART pathways also yielded high sensitivity for acute myocardial infarction (96.9% [95% CI 91.1% to 99.4%] for m-ADAPT and 97.9% [95% CI 92.7% to 99.7%] for EDACS and HEART), but lower sensitivity for acute coronary syndrome (≤95.0% for all). The m-ADAPT, EDACS, and HEART rules classified more patients as being at low risk (64.3%, 62.5%, and 49.8%, respectively) than the new Vancouver Chest Pain Rule and No Objective Testing Rule (28.2% and 34.5%, respectively). Conclusion In this cohort with a low prevalence of acute myocardial infarction and acute coronary syndrome, using the Beckman's Access high-sensitivity troponin I assay with the new Vancouver Chest Pain Rule or No Objective Testing Rule enabled approximately one third of patients to be safely discharged after 2-hour risk stratification with no further testing. The EDACS, m-ADAPT, or HEART pathway enabled half of ED patients to be rapidly referred for objective testing.

Background and Aims: Current tools for risk stratification of chronic liver disease subjects are limited. We aimed to determine whether the serum-based ELF (Enhanced Liver Fibrosis) test predicted liver-related clinical outcomes, or progression to advanced liver disease, and to compare the performance of ELF to liver biopsy and non-invasive algorithms. Methods: Three hundred patients with ELF scores assayed at the time of liver biopsy were followed up (median 6.1 years) for liver-related clinical outcomes (n = 16) and clear evidence of progression to advanced fibrosis (n = 18), by review of medical records and clinical data. Results: Fourteen of 73 (19.2%) patients with ELF score indicative of advanced fibrosis (≥9.8, the manufacturer's cut-off) had a liver-related clinical outcome, compared to only two of 227 (

Background: The purpose of this study was to evaluate a combined κ and λ light chain immunofixation (CLIF) as a screening tool to detect monoclonal immunoglobulins in serum and urine. A secondary aim was to investigate the impact on workflow and reagent utilisation of a systematic implementation of CLIF in addition to routine protein electrophoresis (PE) on all samples. Methods: Light chain antisera ( κ and λ ) were mixed in a 1:1 ratio and loaded in the same sequence as the PE to create a superimposable image. Results: The CLIF procedure agreed significantly better with standard immunofixation procedures in the serum and urine. In 33 (22%) new patients and in 114 (15%) follow-up patients CLIF detected a band missed by PE in serum. In 34 (4.5%) of previously categorised cases the monoclonal band was below the detection limit of CLIF in serum, but still detectable by conventional immunofixation electrophoresis. In one case (0.7%) a band in a urine specimen was missed by CLIF compared to 70 (49%) missed by PE. After the systematic introduction of CLIF turn-around-times (TATs) and utilisation of laboratory consumables decreased significantly (p < 0.001). Conclusions: A systematic implementation of CLIF led to the detection of monoclonal bands missed by PE with an improvement in TATs and a decrease in cost.

BACKGROUND:: Despite significant interindividual variability in prednisolone pharmacokinetics and potentially serious consequences with inadequate or excessive exposure, monitoring of prednisolone levels is not employed to guide therapy. As ultrahigh-performance liquid chromatography-tandem mass spectrometry methods can now measure the active free fraction of prednisolone, this study aimed to evaluate the performance of 15 published limited sampling strategies (LSSs) for predicting free prednisolone exposure in adult kidney transplant recipients and to examine the relationship between free/total prednisolone exposure and plasma glucose. METHODS:: The study was performed in 11 subjects without diabetes 3-4 weeks postkidney transplantation. Area under the concentration time curve profiles of total and free prednisolone from 0 to 12 hours postdose (AUC0-12) were determined and compared with predicted AUC0-12 values calculated from published LSSs. Venous glucose was measured concurrently with the 13 sampling time points. RESULTS:: The mean (±SD) age of subjects was 52 ± 12 years, 5 were men and the median (interquartile range) daily prednisolone dose was 20.0 mg (20.0-22.5). Interindividual variation in dose-adjusted free and total prednisolone exposure was 1.9-and 3.2-fold, respectively. All 15 free prednisolone LSSs exhibited good correlation (r ≥ 0.83), with bias and imprecision less than 15%. An LSS incorporating 1.25-and 3-hour samples had the highest predictive power (r = 0.97, bias 1.2%, imprecision 5.6%). Free prednisolone AUC0-12 correlated with peak glucose levels (r = 0.65, P = 0.037), as did predicted AUC0-12 from 14/15 LSSs. CONCLUSIONS:: Biologically active free prednisolone exposure can be accurately predicted postkidney transplantation by LSSs incorporating 2-point concentration sampling. Peak plasma glucose concentration correlated well with prednisolone exposure.

Emerging evidence suggests that uremic toxins, in particular indoxyl sulfate (IS) and p-cresyl sulfate (PCS), may be involved in the pathogenesis of cardiovascular disease. Despite a significant increase in IS and PCS in patients with established kidney damage, the effect of a nephrectomy in non-chronic kidney disease patients is not yet known.Forty-two living kidney donors (Caucasian; 76% female [n=32]; 53 ± 10 years) were enrolled in an observational cohort study and followed up annually for 2 years (before nephrectomy, 1 and 2 years after nephrectomy). At each time point, patients underwent measurements of serum total and free IS and PCS (using ultrahigh-performance liquid chromatography), carotid intima-media thickness (a measure of arterial stiffness), brachial artery reactivity (both flow-mediated dilatation and sublingual glycerol trinitrate, markers of endothelial dysfunction), kidney function by Chronic Kidney Disease Epidemiology Collaboration creatinine-cystatin C, and urate and high-sensitivity C-reactive protein using standard laboratory techniques.Kidney function decreased by 30% after nephrectomy (absolute change estimated glomerular filtration rate 28 ± 6.9 and 27 ± 7.6 mL/min/1.73 m at 1 and 2 years, respectively), and the concentration of toxin levels increased by 44% to 100%, which remained elevated at 2 years after nephrectomy (all P0.001). Both toxins were associated with carotid intima-media thickness, brachial artery reactivity-glycerol trinitrate, serum urate, and C-reactive protein levels (all P0.03). Further, IS and urate were found to be independent predictors of change in kidney function, from baseline at 2 years after nephrectomy (both P0.03).This study demonstrated significant and sustained increases in nephrovascular toxins, IS and PCS, after nephrectomy. Levels of both toxins were associated with clinically relevant markers of cardiovascular and renal risk, warranting further research in this area.

Objectives Concentrations of troponin measured with high sensitivity troponin assays are raised in a number of emergency department (ED) patients; however many are not diagnosed with acute myocardial infarction (AMI). Clinical comparisons between the early use (2 h after presentation) of high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) assays for the diagnosis of AMI have not been reported. Design and methods Early (0 h and 2 h) hs-cTnT and hs-cTnI assay results in 1571 ED patients with potential acute coronary syndrome (ACS) without ST elevation on electrocardiograph (ECG) were evaluated. The primary outcome was diagnosis of index AMI adjudicated by cardiologists using the local cTnI assay results taken ≥ 6 h after presentation, ECGs and clinical information. Stored samples were later analysed with hs-cTnT and hs-cTnI assays. Results The ROC analysis for AMI (204 patients; 13.0%) for hs-cTnT and hs-cTnI after 2 h was 0.95 (95% CI: 0.94–0.97) and 0.98 (95% CI: 0.97–0.99) respectively. The sensitivity, specificity, PLR, and NLR of hs-cTnT and hs-cTnI for AMI after 2 h were 94.1% (95% CI: 90.0–96.6) and 95.6% (95% CI: 91.8–97.7), 79.0% (95% CI: 76.8–81.1) and 92.5% (95% CI: 90.9–93.7), 4.48 (95% CI: 4.02–5.00) and 12.86 (95% CI: 10.51–15.31), and 0.07 (95% CI: 0.04–0.13) and 0.05 (95% CI:0.03–0.09) respectively. Conclusions Exclusion of AMI 2 h after presentation in emergency patients with possible ACS can be achieved using hs-cTnT or hs-cTnI assays. Significant differences in specificity of these assays are relevant and if using the hs-cTnT assay, further clinical assessment in a larger proportion of patients would be required.

Background Risk stratification processes for patients with possible acute coronary syndrome (ACS) recommend the use of serial sensitive troponin testing over at least 6 h. Troponin assays vary in their analytical performance. Utility in accurate risk stratification at 2 h post-presentation is unknown. Methods A diagnostic accuracy study of patients presenting to the emergency department (ED) with symptoms of ACS was performed. Troponin was measured at 0, 2 and 6 h post-presentation. Acute myocardial infarction (AMI) was adjudicated by cardiologists and incorporated the 0 and 6 h troponin values measured by a sensitive troponin assay. Results were described using standard measures of test accuracy. Results Of the 685 patients, 51 (7.4%) had 30-day AMI or cardiac death, and 76 (11.1%) had secondary outcomes (all cause death, ACS and revascularisation procedures). There was no significant difference in the diagnostic accuracy of early versus late biomarker strategies when used with the current risk stratification processes. Incorporation of a significant delta did not improve the stratification at 2 h post-presentation. Conclusions Accelerated risk stratification of patients with ACS symptoms may occur at 2 h post-presentation using troponin results measured by a sensitive assay. Incorporation of such a strategy could support improvements in patient flow within EDs.

OBJECTIVES To validate an accelerated biomarker strategy using a high-sensitivity cardiac troponin T (hs-cTnT) assay for diagnosing acute myocardial infarction (AMI) in patients presenting to the emergency department with chest pain; and to validate this strategy in combination with the National Heart Foundation of Australia/Cardiac Society of Australia and New Zealand risk stratification model. DESIGN, SETTING AND PATIENTS Single-centre, prospective, observational cohort study of 764 adults presenting to a tertiary hospital with symptoms of possible acute coronary syndrome between November 2008 and February 2011. MAIN OUTCOME MEASURES AMI or cardiac death within 24 hours of presentation (primary), and major adverse cardiac events within 30 days (secondary). RESULTS An elevated hs-cTnT assay result above the 99th percentile at either the 0 h or 2 h time points had sensitivity of 96.4% (95% CI, 87.9%-99.0%), specificity of 82.6% (95% CI, 79.7%-85.2%), negative predictive value of 99.7% (95% CI, 98.8%-99.9%) and positive predictive value of 30.5% (95% CI, 24.2%-37.6%) for diagnosing AMI. Compared with a traditional 6 h cardiac troponin testing strategy, the accelerated strategy led to reclassification of risk in only two patients with adverse cardiac outcomes, with no net effect on appropriate management. CONCLUSIONS In patients presenting with chest pain, an accelerated biomarker strategy using the hs-cTnT assay performed well in the initial diagnosis of AMI. The accelerated strategy was also effective when incorporated into a comprehensive strategy of risk stratification that included clinical and demographic factors. The time saved by this approach could have a major impact on health service delivery. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry ACTRN12610000053022.

Soluble CD30 (sCD30) has been associated with rejection and graft loss in kidney transplantation, leading to the suggestion that sCD30 might be a useful biomarker to adjust immunosuppressant medication dosing. However, there has been minimal study of the influence of individual immunosuppressive drugs on sCD30 levels.To evaluate the influence of mycophenolic acid (MPA), prednisolone, and tacrolimus exposure on sCD30 levels in adult kidney transplant recipients.The sCD30 levels were measured pretransplant and 30 days posttransplant. Area under the concentration-time curve (AUC) for each drug was estimated on day 30 using validated, multiple regression-derived limited sampling strategies.One hundred twenty-five subjects were included. Median (interquartile range) sCD30 levels were lower on day 30 posttransplant compared with pretransplant [10.7 (3.7-20.1) pg/mL versus 66.5 (46.0-95.1) pg/mL; P0.0001]. On univariate analyses, day 30 sCD30 levels were negatively correlated with MPA exposure and positively correlated with tacrolimus exposure. Using multivariate logistic regression, higher tacrolimus exposure was independently associated with higher day 30 sCD30 levels (2.2 change in odds for an SD increase in tacrolimus AUC 0-12, P = 0.01; 5.5 change in odds for an SD increase in tacrolimus predose concentration, P0.0001). In contrast, MPA and total and free prednisolone exposures were not independently associated with sCD30 levels.The sCD30 levels are significantly reduced in the presence of combination immunosuppression but are differentially affected by different immunosuppressant agents. More research is required before introduction of sCD30 measurement into clinical practice can be considered.

A reliable biomarker is required in hepatology clinics for detection and follow-up of heavy alcohol consumption. Carbohydrate-deficient transferrin (CDT) increases with sustained heavy alcohol consumption and is the most specific biomarker of ethanol (EtOH) consumption. Recent introduction of a standardized method for measuring CDT has improved its clinical application. This study was designed to determine whether alcohol-independent factors influence CDT levels in patients with chronic liver disease (CLD).The relationship between serum %CDT and self-reported history of alcohol consumption was examined in 254 patients referred for evaluation of liver disease. CDT analysis was performed on serum collected at time of liver biopsy.CDT levels were not affected by severity or etiology of nonalcoholic liver disease. Thirteen of 254 subjects had a %CDT1.7, predictive of heavy alcohol intake, 6 of whom did not acknowledge heavy drinking. Twelve of these 13 subjects were suspected heavy drinkers on review of their medical records and clinical results. Conversely, not all acknowledged heavy drinkers had %CDT1.7. Heavy drinkers with a body mass index (BMI) in the overweight or obese range had significantly lower %CDT than lean heavy drinkers. This persisted even when lean body weight was used as an approximation of the EtOH volume of distribution.An elevated BMI reduces the diagnostic utility of CDT at higher alcohol intake in subjects with CLD using the standardized method. In a hepatology outpatient setting, this assay is likely to be useful to confirm suspicion of heavy drinking in subjects who are not overweight, but cannot reliably identify moderate drinkers or heavy drinkers who are overweight.

Pregnane X, encoded by the gene NR112, is a nuclear receptor whose primary role is to promote the detoxification and clearance of drugs and other foreign compounds from the body.The aim of this study was to analyze associations between NR1I2 polymorphisms, immunosuppressant drug exposure, and clinical outcomes in adult kidney transplant recipients.Exposures to tacrolimus, mycophenolic acid, and total and free prednisolone were estimated at month 1 posttransplant using validated multiple regression-derived limited sampling strategies.In the 158 subjects studied, median (interquartile range) dose-adjusted exposure to tacrolimus was significantly higher in individuals carrying the NR1I2 8055T variant allele, when compared with exposure in wild-type individuals [20 (14, 22) μg·h/L/mg versus 15 (9, 24) μg·h/L/mg; P =0.0007]. Using multivariable logistic regression, NR1I2 8055T carrier status was independently predictive of higher dose-adjusted tacrolimus exposure (P=0.0005). Moreover, BK viremia was seen significantly more frequently in NR1I2 8055T allele carriers compared with wild-type individuals (38% vs 18%, P=0.005) and possession of the NR1I2 8055T allele imposed significantly higher odds of BK viremia (adjusted odds ratio, 2.76 [95% confidence interval, 1.33-7.73]; P=0.006). No significant difference in geometric mean peak BK viral replication titer was observed between 8055T carriers and noncarriers. No NR1I2 SNP or haplotype was significantly, independently associated with total or free prednisolone or MPA exposure.These data demonstrate an impact of pregnane X receptor polymorphisms on tacrolimus pharmacokinetics. Association of the 8055T allele with BK viremia suggests clinically significant "overimmunosuppression" in individuals with this genotype.