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Secretoneurin (SN) is a novel cardiac biomarker that associates with the risk of mortality and dysfunctional cardiomyocyte Ca2+ handling in heart failure patients. Reference intervals for SN are unknown.SN was measured with a CE-marked ELISA in healthy community dwellers from the fourth wave of the Trøndelag Health Study (HUNT4) conducted in 2017–2019. The common, sex and age specific 90th, 95th, 97.5th and 99th percentiles were calculated using the non-parametric method and outlier exclusion according to the Reed test. The applicability of sex and age specific reference intervals were investigated using Harris and Boyd test. We also estimated the percentiles in a subset with normal findings on echocardiographic screening.The total cohort included 887 persons (56.4 % women). After echocardiographic screening 122 persons were excluded, leaving a total of 765 persons (57.8 % women). The 97.5th percentile (95 % CI in brackets) of SN was 59.7 (57.5–62.1) pmol/L in the total population and 58.6 (57.1–62.1) pmol/L after echocardiography screening. In general, slightly higher percentiles were found in women and elderly participants, but less than 4 % in these subgroups had concentrations deviating from the common 97.5th percentile. Low BMI or eGFR was also associated with higher concentrations of SN.Upper reference limits for SN were similar amongst healthy adult community dwellers regardless of prescreening including cardiac echocardiography or not. Women and elderly showed higher concentrations of SN, but the differences were not sufficiently large to justify age and sex stratified upper reference limits. [ABSTRACT FROM AUTHOR]

Chronic myocardial injury (CMI) is defined as stable concentrations of cardiac troponin T or I (cTnT or cTnI) above the assay-specific 99th percentile upper reference limit (URL) and signals poor outcome. The clinical implications of diagnosing CMI are unclear. We aimed to assess prevalence and association of CMI with long-term prognosis using three different high-sensitivity cTn (hs-cTn) assays. A total of 1,292 hospitalized patients without acute myocardial injury had cTn concentrations quantified by hs-cTn assays by Roche Diagnostics, Abbott Diagnostics and Siemens Healthineers. The median follow-up time was 4.1 years. The prevalence of CMI and hazard ratios for mortality and cardiovascular (CV) events were calculated based on the URL provided by the manufacturers and compared to the prognostic accuracy when lower percentiles of cTn (97.5, 95 or 90), limit of detection or the estimated bioequivalent concentrations between assays were used as cutoff values. There was no major difference in prognostic accuracy between cTnT and cTnI analyzed as continuous variables. The correlation between cTnT and cTnI was high (r=0.724–0.785), but the cTnT assay diagnosed 3.9–4.5 times more patients with having CMI based on the sex-specific URLs (TnT, n=207; TnI Abbott, n=46, TnI Siemens, n=53) and had higher clinical sensitivity and AUC at the URL. The prevalence of CMI is highly assay-dependent. cTnT and cTnI have similar prognostic accuracy for mortality or CV events when measured as continuous variables. However, a CMI diagnosis according to cTnT has higher prognostic accuracy compared to a CMI diagnosis according to cTnI. [ABSTRACT FROM AUTHOR]

The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results. [ABSTRACT FROM AUTHOR]

The International Federation of Clinical Chemistry and Laboarator Medicine (IFCC) Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has provided evidence-based educational resources to aid and improve the understanding of important analytical and clinical aspects of cardiac biomarkers. The present IFCC C-CB educational report focuses on recommendations for appropriate use, analytical performance, and gaps in clinical studies related to the use of cardiac troponin (cTn) by point of care (POC) measurement, often referred to as a point of care testing (POCT). The use of high-sensitivity (hs)-cTn POC devices in accelerated diagnostic protocols used in emergency departments or outpatient clinics investigating acute coronary syndrome has the potential for improved efficacy, reduction of length of stay and reduced costs in the health care system. POCT workflow integration includes location of the instrument, assignment of collection and testing responsibility to (non-lab) staff, instrument maintenance, in-service and recurrent training, quality control, proficiency assessments, discrepant result trapping, and troubleshooting and inventory management. [ABSTRACT FROM AUTHOR]

Sample analysis All serum samples were tested in duplicate on the Erenna SP ® sp platform by EMD Millipore Corporation, Hayward California. However, our CV SB A sb % was obtained from duplicates with median cMyC of 4.38 (2.75-5.97) ng/L, which is considerably lower than median cMyC found in patient with adjudicated diagnosis of acute coronary syndrome 237 (71-876) ng/L in the APACE cohort [[6]], and only ~5% of the 99th percentile (derived from patients without coronary artery disease) [[28]]. Analysis, confined to the initial presentation blood sample, showed that cMyC is at least as good as cardiac troponin measured with the leading assays in predicting the diagnosis of AMI, mortality and future cardiovascular events [[6]]. Keywords: biological variation; cardiac myosin-binding protein C; index of individuality; reference change value EN biological variation cardiac myosin-binding protein C index of individuality reference change value 576 583 8 03/11/22 20220301 NES 220301 Introduction Cardiac myosin-binding protein C (cMyC) is a novel biomarker of myocardial injury that was first identified in cardiac venous effluent approximately 10 years ago [[1]]. [Extracted from the article]

Recommended sample handling and pre-analytical factors that impact the stability of ABG-samples are well documented [[3]] and are likely interchangeable in with VBG-samples if factors related to oxygen stability are ignored. Six out of the eight laboratories with published procedures for VBG-testing opted to use evacuated lithium-heparin tubes instead of recommended air-tight blood gas syringes (BGS), and two out of eight laboratories stored VBG-samples on ice. Accordingly, we undertook a study investigating the stability of the acid/base parameters pH, pCO SB 2 sb , cHCO SB 3 sb SP - sp , and lactate in VBG-samples at room temperature vs. ice and BGS vs. lithium-heparin tubes. [Extracted from the article]

The joint consensus panel of the European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently addressed present and future challenges in the laboratory diagnostics of atherogenic lipoproteins. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDLC), LDL cholesterol (LDLC), and calculated non-HDLC (=total – HDLC) constitute the primary lipid panel for estimating risk of atherosclerotic cardiovascular disease (ASCVD) and can be measured in the nonfasting state. LDLC is the primary target of lipid-lowering therapies. For on-treatment follow-up, LDLC shall be measured or calculated by the same method to attenuate errors in treatment decisions due to marked between-method variations. Lipoprotein(a) [Lp(a)]-cholesterol is part of measured or calculated LDLC and should be estimated at least once in all patients at risk of ASCVD, especially in those whose LDLC declines poorly upon statin treatment. Residual risk of ASCVD even under optimal LDL-lowering treatment should be also assessed by non-HDLC or apolipoprotein B (apoB), especially in patients with mild-to-moderate hypertriglyceridemia (2–10 mmol/L). Non-HDLC includes the assessment of remnant lipoprotein cholesterol and shall be reported in all standard lipid panels. Additional apoB measurement can detect elevated LDL particle (LDLP) numbers often unidentified on the basis of LDLC alone. Reference intervals of lipids, lipoproteins, and apolipoproteins are reported for European men and women aged 20–100 years. However, laboratories shall flag abnormal lipid values with reference to therapeutic decision thresholds. [ABSTRACT FROM AUTHOR]

Background: There is increasing interest in direct patient engagement including receiving their laboratory medicine results. We previously established an appetite for Specialists in Laboratory Medicine to support patients in understanding results. The aim of this study was to establish whether patients agreed with such an approach, determined through surveying views in eight European countries. Methods: A standardized five-question survey was administered across eight European countries to a total of 1084 individuals attending medical outpatient clinics, with 100 patients each in Poland, Serbia, Netherlands, Turkey and Czech Republic, 101 in Estonia, 116 in Denmark and 367 in Norway. The responses across countries were compared using the chi-square test (p < 0.05). Results: Patients wanting their results ranged from 50% to 94% (mean 65%) of those responding positively, a mean of 72% wanted additional information with their results; direct receipt was preferred over referral to a website. Specialists in Laboratory Medicine providing such information were acceptable to a mean of 62% of those respondents wishing their results; in countries where payment was possible, there was little interest in making additional payment for such a service. Conclusions: A clear proportion of patients are interested in receiving their laboratory medicine results, the majority with explanatory notes; a role for Specialists in Laboratory Medicine is acceptable and raises the potential for direct engagement by such specialists with patients offering a new paradigm for the provision of laboratory medicine activities. [ABSTRACT FROM AUTHOR]

Background: Middle- and long-term biological variation data for hematological parameters have been reported in the literature. Within-day 24-h variability profiles for hematological parameters are currently lacking. However, comprehensive hour-to-hour variability data are critical to detect diurnal cyclical rhythms, and to take into account the 'time of sample collection' as a possible determinant of natural fluctuation. In this study, we assessed 24-h variation profiles for 20 hematological parameters. Methods: Blood samples were collected under standardized conditions from 24 subjects every hour for 24 h. At each measurement, 20 hematological parameters were determined in duplicate. Analytical variation (CVA), within-subject biological variation (CVI), between-subject biological variation (CVG), index of individuality (II), and reference change values (RCVs) were calculated. For the parameters with a diurnal rhythm, hour-to-hour RCVs were determined. Results: All parameters showed higher CVG than CVI. Highest CVG was found for eosinophils (46.6%; 95% CI, 34.9%-70.1%) and the lowest value was mean corpuscular hemoglobin concentration (MCHC) (3.2%; 95% CI, 2.4%-4.8%). CVI varied from 0.4% (95% CI, 0.32%-0.42%) to 20.9% (95% CI, 19.4%-22.6%) for red cell distribution width (RDW) and eosinophils, respectively. Six hematological parameters showed a diurnal rhythm. Conclusions: We present complete 24-h variability profiles for 20 hematological parameters. Hour-to-hour reference changes values may help to better discriminate between random fluctuations and true changes in parameters with rhythmic diurnal oscillations. [ABSTRACT FROM AUTHOR]

Background: Correct information provided by guidelines may reduce laboratory test related errors during the pre-analytical, analytical and post-analytical phase and increase the quality of laboratory results. Methods: Twelve clinical practice guidelines were reviewed regarding inclusion of important laboratory investigations. Based on the results and the authors' experience, two checklists were developed: one comprehensive list including topics that authors of guidelines may consider and one consisting of minimal standards that should be covered for all laboratory tests recommended in clinical practice guidelines. The number of topics addressed by the guidelines was related to involvement of laboratory medicine specialists in the guideline development process. Results: The comprehensive list suggests 33 pre- analytical, 37 analytical and 10 post-analytical items. The mean percentage of topics dealt with by the guidelines was 33% (median 30%, range 17%-55%) and inclusion of a laboratory medicine specialist in the guideline committee significantly increased the number of topics addressed. Information about patient status, biological and analytical interferences and sample handling were scarce in most guidelines even if the inclusion of a laboratory medicine specialist in the development process seemingly led to increased focus on, e.g., sample type, sample handling and analytical variation. Examples underlining the importance of including laboratory items are given. Conclusions: Inclusion of laboratory medicine specialist in the guideline development process may increase the focus on important laboratory related items even if this information is usually limited. Two checklists are suggested to help guideline developers to cover all important topics related to laboratory testing. [ABSTRACT FROM AUTHOR]

Reflective testing is a procedure in which the laboratory specialist adds additional tests and/or comments to an original request, after inspection (reflection) of the results. It can be considered as an extension of the authorization process where laboratory tests are inspected before reporting to the physician. The laboratory specialist will inevitably find inconclusive results, and additional testing can contribute to make the appropriate diagnosis. Several studies have been published on the effects of reflective testing. Some studies focus on the opinion of the general practitioners or other clinicians, whereas other studies were intended to determine the patient's perspective. Overall, reflective testing was judged as a useful way to improve the process of diagnosing (and treating) patients. There is to date scarce high quality scientific evidence of the effectiveness of this procedure in terms of patient management. A randomized clinical trial investigating this aspect is however ongoing. Cost effectiveness of reflective testing still needs to be determined in the future. In conclusion, reflective testing can be seen as a new dimension in the service of the clinical chemistry laboratory to primary health care. Additional research is needed to deliver the scientific proof of the effectiveness of reflective testing for patient management. [ABSTRACT FROM AUTHOR]