Search

Introduction: The health impact from alcohol is of recognised concern, from acute intoxication as well as increased risk of chronic health issues over time. Identifying factors associated with higher alcohol consumption when presenting to the emergency department (ED) will inform public health policy and enable more targeted health care and appropriate referrals. Methods: Secondary testing of blood samples collected during routine clinical care of 1160 ED patients presenting to the Royal Brisbane and Women's Hospital in Queensland, Australia, for 10 days between 22 January and 1 February 2021. Alcohol was measured by blood ethanol (intake in recent hours) and phosphatidylethanol (PEth; intake over 2–4 weeks). Zero‐inflated negative binomial regression was used to identify demographic and clinical factors associated with higher alcohol concentrations. Results: Males were found to have 83% higher blood ethanol and 32% higher PEth concentrations than females (adjusted rate ratio [ARR] 1.83, 95% confidence interval [CI] 1.37–2.45 and ARR 1.32, 95% CI 1.04–1.68, respectively). Blood ethanol concentrations were 3.4 times higher for those 18–44 years, compared to those aged 65+ (ARR 3.40, 95% CI 2.40–4.82) whereas PEth concentrations were found to be the highest in those aged 45–64 years, being 70% higher than those aged 65+ (ARR 1.70, 95% CI 1.19–2.44). Patients brought in involuntarily had eight‐times higher blood ethanol concentrations than those who self‐attended. Discussion and Conclusions: This study used two alcohol markers to identify factors associated with higher alcohol concentrations in emergency presentations. The findings demonstrate how these biomarkers can provide informative data for public health responses and monitoring of alcohol use trends. [ABSTRACT FROM AUTHOR]

Newborn screening (NBS) assays for spinal muscular atrophy (SMA) typically use a polymerase chain reaction (PCR) based assay to identify individuals with homozygous deletion in exon 7 of the SMN1 gene. Due to high DNA sequence homology between SMN1 and SMN2, it has previously been difficult to accurately bioinformatically map short reads from next-generation DNA sequencing (NGS) to SMN1, resulting in low analytical performance and preventing NGS being used for SMA screening. Advances in bioinformatics have allowed NGS to be used in diagnostic settings, but to date these assays have not reached the scale required for high volume population newborn screening and have not been performed on the dried blood spot samples thatNBS programs currently use. Herewe integrate anNGS assay using hybridisation-based capture with a customised bioinformatics algorithm and purpose designed high throughput reporting software into an existing NBS program to achieve a laboratory workflow for population SMA screening. We tested the NGS assay on over 2500 newborns born over 2 weeks in a NBS program in a technical feasibility study and show high sensitivity and specificity. Our results suggest NGS may be an alternate method for SMA screening by NBS programs, providing a multiplex testing platform on which potentially hundreds of inherited conditions could be simultaneously tested. [ABSTRACT FROM AUTHOR]

Introduction: The aim was to determine the prevalence of alcohol‐related presentations to an emergency department (ED) in a major Australian hospital, through a novel surveillance approach using two biomarkers, blood ethanol and phosphatidylethanol (PEth). Methods: Observational study using secondary testing of blood samples collected during routine clinical care of ED patients presenting to the Royal Brisbane and Women's Hospital in Queensland, Australia, between 22 January and 2 February 2021. Data were collected from 1160 patients during the 10‐day study period. The main outcomes were the prevalence of acute alcohol intake, as determined by blood ethanol, and recent use over 2–4 weeks, as determined by PEth concentrations, for all ED presentations and different diagnostic groups. Results: The overall prevalence for blood ethanol was 9.3% (95% confidence interval [CI] 7.8%, 11.1%), 5.3% for general medical presentations, increasing four‐fold to 22.2% for injury presentations. The overall prevalence of PEth positive samples was 32.5% (95% CI 29.9%, 35.3%) and 41.4% for injury presentations. There were 263 (25.3%) cases that tested negative for acute blood ethanol but positive for PEth concentrations indicative of significant to heavy medium‐term alcohol consumption. Discussion and Conclusions: This novel surveillance approach demonstrates that using blood ethanol tests in isolation significantly underestimates the prevalence of medium‐term alcohol consumption in ED presentations. Prevalence of alcohol use was higher for key diagnostic groups such as injury presentations. Performing periodic measurement of both acute and medium‐term alcohol consumption accurately and objectively in ED presentations, would be valuable for informing targeted public health prevention and control strategies. [ABSTRACT FROM AUTHOR]

Objective: European and Australian guidelines for cystic fibrosis (CF) reproductive carrier screening recommend testing a small number of high frequency CF causing variants, rather than comprehensive CFTR sequencing. The study objective was to determine variant detection rates of commercially available targeted reproductive carrier screening tests in Australia. Methods: Next‐generation DNA sequencing of the CFTR gene was performed on 2552 individuals from a whole population sample to identify CF causing variants. The variant detection rates of two commercially available Australian reproductive carrier screening tests, which target 50 or 175 CF causing variants, in this population were calculated. The ethnicity of individuals was determined using principal component analysis. Results: Variant detection rates of the tests for 50 and 175 CF causing variants were 88.2% and 90.8%, respectively. No CF causing variants in individuals of East Asian ethnicity (n = 3) were detected by either test, while >86.6% (n = 69) of CF causing variants in Europeans would be identified by either test. Conclusions: Reproductive carrier screening tests for a targeted set of high frequency CF variants are unable to detect approximately 10% of CF variants in a multiethnic Australian population, and individuals of East Asian ethnicity are disproportionally affected by this test limitation. Key points: What's already known about this topic? Reproductive carrier screening for cystic fibrosis (CF) is becoming increasingly common in Europe and Australia. European and Australian guidelines recommend testing for a targeted set of the most common CF causing variants. What does this study add? Reproductive carrier screening tests for a targeted set of CF causing variants are unable to detect approximately 10% of CF variants in a multiethnic Australian population and individuals of East Asian ethnicity are disproportionally affected by this limitation of the test. [ABSTRACT FROM AUTHOR]

Protein biosensors play an increasingly important role as reporters for research and clinical applications. Here we present an approach for the construction of fully integrated but modular electrochemical biosensors based on the principal component of glucose monitors PQQ‐glucose dehydrogenase (PQQ‐GDH). We designed allosterically regulated circular permutated variants of PQQ‐GDH that show large (>10‐fold) changes in enzymatic activity following intramolecular scaffolding of the newly generated N‐ and C termini by ligand binding domain/ligand complexes. The developed biosensors demonstrated sub‐nanomolar affinities for small molecules and proteins in colorimetric and electrochemical assays. For instance, the concentration of Cyclosporine A could be measured in 1 μL of undiluted blood with the same accuracy as the leading diagnostic technique that uses 50 times more sample. We further used this biosensor to construct highly porous gold bioelectrodes capable of robustly detecting concentrations of Cyclosporine A as low as 20 pM and retained functionality in samples containing at least 60 % human serum. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Rationale: Whether biomarkers can identify subgroups of patients with septic shock with differential treatment responses to hydrocortisone is unknown.Objectives: To determine if there is heterogeneity in effect for hydrocortisone on mortality, shock resolution, and other clinical outcomes based on baseline cortisol, aldosterone, and ascorbic acid concentrations.Methods: From May 2014 to April 2017, we obtained serum samples from 529 patients with septic shock from 22 ICUs in Australia and New Zealand.Measurements and Main Results: There were no significant interactions between the association with 90-day mortality and treatment with either hydrocortisone or placebo for total cortisol (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.02-1.16 vs. OR, 1.07; 95% CI, 1.00-1.13; P = 0.70), free cortisol (OR, 1.20; 95% CI, 1.04-1.38 vs. OR, 1.16; 95% CI, 1.02-1.32; P = 0.75), aldosterone (OR, 1.01; 95% CI, 0.97-1.05 vs. OR, 1.01; 95% CI, 0.98-1.04; P = 0.99), or ascorbic acid (OR, 1.11; 95% CI, 0.89-1.39 vs. OR, 1.05; 95% CI, 0.91-1.22; P = 0.70), respectively. Similar results were observed for the association with shock resolution. Elevated free cortisol was significantly associated with 90-day mortality (OR, 1.13; 95% CI, 1.00-1.27; P = 0.04), but total cortisol, aldosterone, and ascorbic acid were not.Conclusions: In patients with septic shock, there was no heterogeneity in effect of adjunctive hydrocortisone on mortality, shock resolution, or other clinical outcomes based on cortisol, aldosterone, and ascorbic acid concentrations. Plasma aldosterone and ascorbic acid concentrations are not associated with outcome. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Context Metyrapone is an inhibitor of endogenous adrenal corticosteroid synthesis, which has been proven to be a viable option in controlling maternal serum cortisol concentrations during pregnancy. The infant exposure to maternally ingested metyrapone through breast milk is, however, largely unknown. Case Description We report the excretion of metyrapone into breast milk and subsequent infant exposure from a lactating woman on 250 mg of metyrapone three times daily. Due to limited supply of breast milk, the infant was fed ∼50% breast milk and 50% formula. At steady state, the average concentrations in the studied breast milk and absolute and relative infant doses were 176 µg/L, 26.45 µg/kg/d, and 0.7%, respectively, for metyrapone, and 310 µg/L, 46.52 µg/kg/d, and 1.21% for its active metabolite metyrapol. The breastfed infant was found to have a plasma metyrapone concentration of 0.05 µg/L, with no evidence of disruption to his adrenocortical axis biochemically. Conclusion These findings indicate that maternal metyrapone use during breastfeeding did not pose a notable risk to this breastfed infant. The infants' exposure to metyrapone was further minimized by avoiding nursing for 2 to 3 hours after each metyrapone dose. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A questionable scientific approach to measuring at low concentrations and inappropriate censoring of results below certain cut-offs have resulted in the dichotomous classification of troponin assays based on their so-called analytical sensitivity. The definition of "high-sensitivity" cardiac troponin is flawed. Evidence suggests that its apparent diagnostic superiority may be explained by the censoring of data. In the evaluation of the detection and quantification capabilities of analytical methods we recommend alignment with International Union of Pure and Applied Chemistry (IUPAC) guidelines, including reporting of all results. This will allow the objective evaluation of the diagnostic performance of troponin assays and will render the current troponin assay classification and nomenclature obsolete. [ABSTRACT FROM AUTHOR]

Background and Aim Carbohydrate deficient transferrin (CDT) is the most specific serum biomarker of heavy alcohol consumption, defined as ⩾350-420g alcohol/week. Despite introduction of a standardized reference measurement technique, widespread use of CDT remains limited due to low sensitivity. The aim of this study was to determine the factors that affect diagnostic sensitivity in patients with sustained heavy alcohol intake. Methods Patients with a self-reported history of sustained heavy alcohol consumption were recruited from the hepatology outpatient department or medical wards. Each patient was interviewed with a validated structured questionnaire of alcohol consumption and CDT analysis using the standardized reference measurement technique with high performance liquid chromatography was performed on serum collected at time of interview. Results 52 patients were recruited: 19 from the hepatology outpatient department and 33 from general medical wards. Median alcohol intake was 1013 (range 366-5880) g/week over the preceding two week period. 26 patients had a diagnostic CDT based on a threshold value of %CDT >1.7 indicating heavy alcohol consumption, yielding a sensitivity of 50%. Overweight/obesity (defined as body mass index (BMI) ⩾25 kg/m2 in Caucasians and ⩾23.0 kg/m2 in Asians), female gender and presence of cirrhosis were independently associated with non-diagnostic %CDT (⩽1.7). Conclusions CDT has limited sensitivity as a biomarker of heavy alcohol consumption. Caution should be applied when ordering and interpreting %CDT results, particularly in women, patients with cirrhosis and those with an elevated BMI. [ABSTRACT FROM AUTHOR]

Background: Comparability of cholesterol measurement is clinically required and external quality assurance (EQA) programmes are important to verify the trueness of routine methods. Methods: We developed a gas chromatography-isotope dilution mass spectrometry (GC-IDMS) total cholesterol assay to investigate the cause of a suspected matrix-related negative bias with the Beckman Coulter enzymatic method discovered in an EQA programme. The GC-IDMS method was calibrated with certified reference material and verified against a secondary reference method. Bias between the GC-IDMS and Beckman Coulter methods was estimated according to Clinical and Laboratory Standards Institute (CLSI) protocol EP9-A2 with 40 clinical samples. Results: At clinically important decision levels, no significant bias was demonstrated on patients' samples (all results within a ± 3% limit). A matrix effect confined to the EQA material that affected the Beckman Coulter total cholesterol method was confirmed. Conclusions: The GC-IDMS method is suitable as a higher order total cholesterol method in a routine clinical laboratory. Matrix effects defeat the objectives of EQA schemes by preventing the verification of trueness. Given the importance of obtaining a true cholesterol result without systematic error, we recommend that EQA material without matrix effects should be used. [ABSTRACT FROM AUTHOR]

Background: The clinical utility of serum κ and λ free light chains (FLC) for the diagnosis and prognosis of plasma cell proliferative disorders is well established. We assessed the analytical performance of the N Latex FLC assays and compared it with the Freelite™ assays. Methods: Analytical precision was assessed according to the CLSI EP5-A2 protocol. Method comparison was performed with 116 clinical samples and linearity was assessed on samples with monoclonal and polyclonal elevations of FLC. Analytical bias and variance was measured with two lots of N Latex FLC reagent. Results: The N Latex FLC κ and λ assays had a total coefficient of variation of 5-7% across the analytical range. The slopes were 1.36 and 1.37 and the between-method variances were 40.0% and 45.4%, respectively, compared with the Freelite™. Good agreement in classification was observed for κ, λ and the κ/λ ratio (Cohen's κ 0.84, 0.76 and 0.89). Statistical nonlinearity occurred commonly, but clinically significant non-linearity was observed in only one instance. Between-reagent lot variation was 7.3% and 10% for κ and λ, respectively. Conclusions: The N Latex FLC assay has good precision, did not exhibit gross antigen excess and can be used in clinical practice based on the analytical performance characteristics. [ABSTRACT FROM AUTHOR]

Aims: Troponin (Tn) is the preferred biochemical marker for the diagnosis of acute coronary syndrome. Spurious false Tn results (outliers) may cause significant problems with clinical management. We investigated the occurrence of outliers and whether this phenomenon could be explained by analytical imprecision. Methods and results: Troponin I (TnI) was measured in duplicate with Beckman AccuTnI reagent if the first TnI result was ≥0.04 μg/L (n = 5265). All TnI requests were performed in duplicate in a subset of samples for one calendar month (n = 881). A total of 13,178 TnI requests were received during the study period. Variables were sample type, centrifugation speed and analyser. Results were identified as outliers when the difference between two results exceeded a critical difference (CD) limit defined by CD = z × √2 × SDAnalytical. Outliers at the 0.0005 probability level were detected in 102 of 5265 duplicate observations (1.94±0.37%). This translated into an outlier rate of 0.55±0.13% for all TnI results and 1.37±0.31% for results above 0.04 mg/L. Outliers resulted only in falsely elevated TnI values and were not dependent on the analyser, centrifugation speed or sample type. Conclusion: TnI outliers occurred more frequently than anticipated, could not be explained by analytical imprecision and indicated a lack of robustness in the assay. The high rate and the magnitude of the errors will complicate clinical management and carry a risk of detrimental patient outcome. The outlier rate is a useful parameter to define the robustness of assays. [ABSTRACT FROM AUTHOR]

Background: False-positive cardiac troponin I results as a result of carryover have previously been reported on the Beckman Coulter AccuTnI assay. We sought to determine if the carryover problem had been resolved with the new AccuTnI + 3 assay.Methods: Carryover experiments were performed in parallel on the Beckman Coulter Access2 analyser using the legacy AccuTnI and new AccuTnI + 3 assays. The same negative patient pool sample was analysed before and after a single analysis of an extremely elevated patient sample.Results: Analysis of a single extremely high sample caused elevations above the 99th percentile cut-off, and thus false-positive cardiac troponin I results on both assays. Both assays demonstrated carryover and subsequent further elevations in negative pool results the following day.Conclusions: Our study replicates our previously published findings of carryover and reagent pack contamination on the AccuTnI assay. Despite improvements on the new AccuTnI + 3 assay, carryover and reagent pack contamination are still present. [ABSTRACT FROM AUTHOR]

Although glycated haemoglobin (HbA(1c)) has become the key biochemical marker of long-term glycaemic control, analytical method-dependent differences in results can occur when haemoglobin variants are present or HbA(1c) is reduced by decreased red cell survival. When the measured HbA(1c) level is discordant with the patient's blood glucose measurements and clinical status, fructosamine is an alternative biochemical marker that can provide a more accurate estimate of the glycaemic control and enable clinicians to appropriately manage patients. [ABSTRACT FROM AUTHOR]

The article presents the case of a 65 year old obese man with a history of type 2 diabetes mellitus brought to a diabetes clinic in January 2008 to stabilize his blood sugar levels. It notes a decrease in the patient's HbA1c level which is found inconsistent with the home blood measurements. According to the article, a discordant HbA1c result should be rechecked with an alternative analytical method. It was found that glucose tests maybe more reliable when there is uncertainty in the long-term markers of glycaemic control.