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Context.—: A relevant portion of coronavirus disease 2019 (COVID-19) patients develop severe disease with negative outcomes. Several biomarkers have been proposed to predict COVID-19 severity, but no definite interpretative criteria have been established to date for stratifying risk., Objective.—: To evaluate 6 serum biomarkers (C-reactive protein, lactate dehydrogenase, D-dimer, albumin, ferritin, and cardiac troponin T) for predicting COVID-19 severity and to define related cutoffs able to aid clinicians in risk stratification of hospitalized patients., Design.—: A retrospective study of 427 COVID-19 patients was performed. Patients were divided into groups based on their clinical outcome: nonsurvivors versus survivors and patients admitted to an intensive care unit versus others. Receiver operating characteristic curves and likelihood ratios were employed to define predictive cutoffs for evaluated markers., Results.—: Marker concentrations at peak were significantly different between groups for both selected outcomes. At univariate logistic regression analysis, all parameters were significantly associated with higher odds of death and intensive care. At the multivariate analysis, high concentrations of lactate dehydrogenase and low concentrations of albumin in serum remained significantly associated with higher odds of death, whereas only low lactate dehydrogenase activities remained associated with lower odds of intensive care admission. The best cutoffs for death prediction were greater than 731 U/L for lactate dehydrogenase and 18 g/L or lower for albumin, whereas a lactate dehydrogenase activity lower than 425 U/L was associated with a negative likelihood ratio of 0.10 for intensive treatment., Conclusions.—: Our study identifies which biochemistry tests represent major predictors of COVID-19 severity and defines the best cutoffs for their use., (© 2020 College of American Pathologists.)

Purpose: To describe the baseline, 1 hr and delta high sensitivity cardiac troponin (hs-cTnT) values in patients with suspected acute myocardial infarction (AMI) but without a final acute coronary syndrome (ACS) diagnosis., Materials and Methods: hs-cTnT assay for RAPID rule out of acute myocardial infarction (TRAPID-AMI) was a prospective diagnostic trial that enrolled emergency department (ED) patients with suspected AMI. Final patient diagnoses were adjudicated by a clinical events committee and subjects placed in different clinical groups: AMI, unstable angina, non-ACS cardiac, non-cardiac and unknown origin. The baseline, 1 hr and delta hs-cTnT values were analysed in the 902 non-ACS patients., Results: Amongst the 1282 studied the patient groups were 213 (17%) AMI, 167 (13%) unstable angina, 113 (9%) non-ACS cardiac, 288 (22%) non-cardiac and 501 (39%) unknown origin. The hs-cTnT values in the non-cardiac and unknown origin groups were combined. The median hs-cTnT values (ng/L) were higher (p < 0.001) in the non-ACS cardiac compared to the non-cardiac/unknown origin group at baseline (11.8, <5) and 1 hr (12.3, <5). Their negative predictive values were 0.955 (baseline) and 0.954 (1 hr) for predicting non-ACS cardiac versus non-cardiac/unknown origin diagnoses., Conclusions: Hs-cTnT may help predict whether non-ACS ED patients have a final non-ACS cardiac or non-cardiac/unknown origin diagnoses.

Background: We evaluated the effect of kidney glomerular function on serum concentrations of human epididymis protein 4 (HE4) using creatinine (Cr), cystatin C (CysC) and related chronic kidney disease epidemiology collaboration (CKD-EPI) equations., Methods: We enrolled 101 women aged ≤56 years with a glomerular filtration rate (GFR) (estimated by CKD-EPI eGFRCr) ranging from 60 to 120 mL/min/1.73 m2, free of any disease and biological and life-style factors known to influence serum HE4 concentrations, and we measured serum Cr, CysC and HE4 concentrations. Cr and CysC values were included in the three CKD-EPI equations to obtain GFR estimates., Results: A statistically significant increase in HE4 median concentrations was detected in subjects with an eGFRCr between 60 and 74 mL/min/1.73 m2 when compared with those with an eGFR >90 mL/min/1.73 m2 (54.2 vs. 42.2 pmol/L, p=0.003). Regression models showed that CysC measurement per se and eGFRCysC were the most sensitive markers to catch HE4 increases due to a mild decrease in renal function [adjusted r2, 0.38 (p=0.00003) and 0.37 (p=0.0004), respectively]. By assuming baseline CysC and eGFRCysC at 0.80 mg/L and 101.5 mL/min/1.73 m2, an increase of 0.10 mg/L in CysC concentrations and a decrease of 10 mL/min of eGFRCysC implied an average (±SE) increase in serum HE4 concentrations of 9.2 (±1.2) and 8.8 (±1.1) pmol/L, respectively., Conclusions: Our study shows that a better estimate of the effect of GFR on serum HE4 is obtained by measuring CysC in serum or using CKD-EPI eGFRCysC equation.

Background: An increased focus on the biological behaviour of serum biomarkers for ovarian cancer, i.e., carbohydrate antigen 125 (CA-125) and human epididymis protein 4 (HE4), has been advocated to improve their clinical use. Due to the paucity and poor design of available studies evaluating biological variation (BV) of CA-125 and the lack of BV data for HE4, in this study we evaluated BV of both biomarkers., Methods: Monthly we obtained serum samples from 14 pre- (PreM) and 14 post-menopausal (PostM) healthy women for 4 consecutive months. Once all samples were available, they were analysed in a single run in duplicate for CA-125 and HE4 on Roche Modular system. Data were analysed by ANOVA., Results: For both biomarkers no difference in median concentrations was found between PreM and PostM. For CA-125 the intra-individual CV (CVI) was not different between groups (9.1% in both). For HE4 CVI was higher in PreM (12.1%) than in PostM (6.5%) (p<0.001). Between-subject CVs were 10.6% for CA-125 and 16.4% for HE4, with no influence by the fertility status. Both biomarkers showed high individuality meaning that the use of population-based reference limits may have limited value for their interpretation. Reference change values were 26% for CA-125 (all), 34% for HE4 PreM and 18% for HE4 PostM., Conclusions: Monitoring longitudinal changes in serum concentrations of ovarian cancer biomarkers over time is probably better than using single threshold rules. According to differences in BV due to the hormonal status, one should differently interpret HE4 changes in PreM and PostM.

Despite the growing interest in hepcidin and other relatively new biomarkers, guidelines and clinical pathways continue to recommend traditional markers, such as serum transferrin (Tf) and ferritin, as laboratory tests for the diagnostic evaluation of iron-related disorders. In this study, we aimed to critically evaluate the diagnostic role of Tf relying on the highest level of available evidence by a comprehensive literature search. The role of Tf in iron deficiency (ID) and iron overload (IO) syndrome as well as a risk marker was evaluated. The low accuracy of Tf and Tf saturation (TS) in the diagnosis and management of ID conditions does not permit definitively recommending their use, even if recently published guidelines still consider the TS investigation as a complementary test for ferritin. If a tissue IO is suspected, TS is often used, even if it may not be the best test for detecting this condition. Nevertheless, clinical guidelines strongly recommend the use of TS as a first-level test for performing genetic diagnosis of hereditary hemochromatosis. Recently reported data indicating elevated TS as a risk factor for diabetes mellitus, cancer, and total mortality, may provide useful additions to the debate over whether or not to screen for IO using TS., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: C-reactive protein (CRP) is recognized as a marker of cardiovascular risk. The biologic variability of CRP is crucial to understanding its significance in estimation of individual risk and subsequent changes in serial analyses., Methods: We systematically reviewed publications on biologic variation of CRP to evaluate the consistency of available data. Data was evaluated with attention to number and type of enrolled subjects, duration of study, frequency of sample collection, sample type, sample storage, analytical methodology, assay sensitivity and statistical analysis., Results: A total of eleven studies on CRP biologic variability were recruited from literature. The majority of studies were limited by choice of analytic methodology, population selection, protocol application, and statistical analysis. Unfortunately, the only study that fulfilled all major pre-analytical, analytical and post-analytical requirements derived biologic variability from logarithmically transformed data, thus making application to clinical practice difficult., Conclusions: There is a paucity of robust data on biologic CRP variability in serum. It is obvious that additional well defined studies are needed to define reliable values of reference change values and of number of samples required to estimate the individual's cardiovascular risk by CRP., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Today, the increase of the blood concentration of cardiac troponins is designated as surrogate for cardiac necrosis and myocardial infarction, when an appropriate clinical and/or instrumental situation is present. As cardiac troponins reflect myocyte death, biomarkers of reversible myocardial damage in the absence of necrosis are, however, still needed to detect the presence of damage even before the irreversible injury is induced and identify "vulnerable" patients before major events occur, permitting adequate treatment. Markers of plaque destabilization and/or markers of myocardial ischemia could be enormously valuable in the emergency department setting if shown to contribute additional independent diagnostic information. However, a new cardiac biomarker is of definitive clinical value only if adequate assays for its measurement are available, its predictive value is defined in the right clinical context, optimal cut-off and release kinetics are known, demonstration of the marker incremental value is clear, there is consistency of marker performance across different settings, and, more importantly, there are data on the effect on patient management and outcome and on cost-effectiveness. Despite the emergence of multiple candidates, sufficient evidence for any of these has yet been demonstrated to recommend their adoption into clinical practice.

This paper reviews the current contribution of the biochemical marker determination to clinical cardiology and discusses some important developments in this field. Biochemical markers play a pivotal role in the diagnosis and management of patients with acute coronary syndrome (ACS), as witnessed by the incorporation of cardiac troponins into new international guidelines for patients with ACS and in the re-definition of myocardial infarction. Despite the success of cardiac troponins, there is still a need for the development of early markers that can reliably rule out ACS from the emergency room at presentation and also detect myocardial ischaemia in the absence of irreversible myocyte injury. Under investigation are two classes of indicators: markers of early injury/ischaemia and markers of inflammation and coronary plaque instability and disruption. Finally, with the characterisation of the cardiac natriuretic peptides, Laboratory Medicine is also assuming a role in the assessment of cardiac function.

Cardiac markers are measured by a number of different immunoassays using specific antibodies directed to the respective antigens. Lacking assay standardization, different results from different assays measuring the same marker may be obtained and this problem may cloud interpretations of reported data. Presently, there are no reference procedures for cardiac markers; certified reference materials should still be established and, at least for cardiac troponins, the analyte in the patients' blood is significantly different from newly synthesized protein. It is therefore clear that the problems of cardiac marker standardization will not be quickly solved. A number of projects are, however, underway under the auspices of the IFCC and other organizations. The aim of this opinion is to reflect on some concepts related to the implementation of a metrologically correct measurement system, giving practical examples on how these concepts can be applied to immunoassays measuring cardiac markers.

New biomarkers, such as cardiac troponins, have a major role to play for cost-effective management of individuals with acute chest pain and suspected coronary syndrome, and the laboratory is now poised to assume a vital role in assessing damage and determining prognosis. The redefined biochemical criterion proposed to classify acute coronary syndrome patients presenting with ischemic symptoms as patients with myocardial infarction is heavily predicated on an increased troponin concentration in blood. In an era of evidence-based medicine, we can no longer overlook the diagnostic and prognostic benefits provided by the measurement of these highly sensitive and specific proteins.

Cardiac markers are presently a hot topic, with active debate on their use. They now have a major role for cost-effective management of acute chest pain and suspected acute coronary syndrome. The laboratory has a pivotal role in proper selection and interpretation of available markers, depending on the creation of evidence-based knowledge about test utilization and sources of variation. This article reviews this knowledge in the field of biomarkers determination and summarizes the major analytic and clinical issues, with reference to various recent recommendations of laboratory medicine and cardiology expert groups.

Context: Elevated cardiac troponin levels have been reported to identify unstable angina patients at high risk., Objective: To examine the relation of cardiac troponin I (cTnI) and cardiac troponin T (cTnT) levels to findings of coronary angiography in these patients., Methods: Samples for troponin estimation were taken every 4 hours throughout the first 48 hours after admission before angiography in 34 patients with primary unstable angina. Patients were considered to be troponin positive if the marker was increased (>0.04 microg/L for cTnT and >0.03 microg/L for cTnI) in at least one sample collected., Results: An increased troponin (I or T) concentration was documented in 14 patients (41.2%). Twelve patients (35.3%) had elevations of both markers, whereas the remaining 2 patients had elevations of cTnI or cTnT alone. Patients with or without increased troponin levels did not differ with respect to degree of coronary disease at angiography. However, patients with elevated troponin concentrations had more complex lesion characteristics. In 69% of patients with increased cTnI levels and in 77% of patients with increased cTnT levels, type B2 or C lesions were documented with presence of ulcerated plaques and thrombus formation. In contrast, only 23% of the patients with elevated cTnI or cTnT levels had type A lesions compared with 71% of patients with negative troponin concentrations., Conclusions: Patients with unstable angina who have significant release of cTnI and/or cTnT have evidence of more complex lesions on coronary angiography, supporting the hypothesis that both troponins might be used without distinction as surrogate markers for microembolization from thrombus formation on a disrupted plaque.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial disease with limited therapeutic options. The measurement of Krebs von den Lungen-6 (KL-6) glycoprotein has been proposed for evaluating the risk of IPF progression and predicting patient prognosis, but the robustness of available evidence is unclear. We searched Medline and Embase databases for peer-reviewed literature from inception to April 2020. Original articles investigating KL-6 as prognostic marker for IPF were retrieved. Considered outcomes were the risk of developing acute exacerbation (AE) and patient survival. Meta-analysis of selected studies was conducted, and quantitative data were uniformed as odds ratio (OR) or hazard ratio (HR) estimates, with corresponding 95% confidence intervals (CI). Twenty-six studies were included in the systematic review and 14 were finally meta-analysed. For AE development, the pooled OR (seven studies) for KL-6 was 2.72 (CI 1.22–6.06; p=0.015). However, a high degree of heterogeneity (I2=85.6%) was found among selected studies. Using data from three studies reporting binary data, a pooled sensitivity of 72% (CI 60–82%) and a specificity of 60% (CI 52–68%) were found for KL-6 measurement in detecting insurgence of AE in IPF patients. Pooled HR (seven studies) for mortality prediction was 1.009 (CI 0.983–1.036; p=0.505). Although our meta-analysis suggested that IPF patients with increased KL-6 concentrations had a significant increased risk of developing AE, the detection power of the evaluated biomarker is limited. Furthermore, no relationship between biomarker concentrations and mortality was found. Caution is also needed when extending obtained results to non-Asian populations. [ABSTRACT FROM AUTHOR]

Background: Measurement of human epididymis protein 4 (HE4) in serum has recently been proposed for clinical use in the framework of ovarian cancer (OvCa). We sought to retrace the translational phase and the clinical implementation steps boosting HE4's clinical value and discuss the effects of its introduction on the diagnostic and management pathways. Methods: Meta-analyses of running evidence have preliminarily suggested that HE4 may overcome carbohydrate antigen 125 (CA125) in identifying OvCa, showing however several gaps that need to be considered, i.e. definition of biomarker diagnostic performance in the early detection of OvCa, added diagnostic value, biological and lifestyle factors of variation, and optimal interpretative criteria. Investigation of the influencing factors has shown that renal impairment represents a major limitation for HE4's diagnostic power. On the other hand, the demonstration of the substantial equivalence of results obtained by commercially available assays allows recommending harmonized thresholds for diagnostic purpose, even if the study of HE4's biological variation has clarified that the longitudinal interpretation of the biomarker changes according to the reference change value could be more appropriate. Summary: We used HE4 as an example for describing the long and bumpy road for making a new biomarker a reality, and the issues that should be checked and the information that should be provided in moving a novel biomarker from its discovery to an effective clinical adoption. [ABSTRACT FROM AUTHOR]

The article discusses a study conducted to verify agreement and bias of automated methods vs. EIA for patients' management. It is noted that serum human epididymis protein 4 (HE4) has gained relevance as an ovarian cancer (OC) biomarker and new automated methods have replaced the first released manual EIA.

Background: As a part of an International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) project to prepare a commutable reference material for cardiac troponin I (cTnI), a pilot study evaluated current cTnI assays for measurement equivalence and their standardization capability. Methods: cTnI-positive samples collected from 90 patients with suspected acute myocardial infarction were assessed for method comparison by 16 cTnI commercial assays according to predefined testing protocols. Seven serum pools prepared from these samples were also assessed. Results: Each assay was assessed against median cTnI concentrations measured by 16 cTnI assays using Passing-Bablok regression analysis of 79 patient samples with values above each assay's declared detection limit. We observed a 10-fold difference in cTnI concentrations for lowest to highest measurement results. After mathematical recalibration of assays, the between-assay variation for patient samples reduced on average from 40% to 22% at low cTnI concentration, 37%-20% at medium concentration, and 29%-14% at high concentration. The average reduction for pools was larger at 16%, 13% and 7% for low, medium and high cTnI concentrations, respectively. Overall, assays demonstrated negligible bias after recalibration (y-intercept: -1.4 to 0.3 ng/L); however, a few samples showed substantial positive and/or negative differences for individual cTnI assays. Conclusions: All of the 16 commercial cTnI assays evaluated in the study demonstrated a significantly higher degree of measurement equivalence after mathematical recalibration, indicating that measurement harmonization or standardization would be effective at reducing inter-assay bias. Pooled sera behaved similarly to individual samples in most assays. [ABSTRACT FROM AUTHOR]

The National Institute for Health and Clinical Excellence (NICE) guidelines have sparked hot debate regarding the role of carbohydrate antigen 125 (CA-125) for ovarian cancer (OC) detection. Recent literature and evidence calls into question the use of CA-125 in diagnostic algorithms, given the better performance of human epididymis protein 4 (HE4) vs. CA-125 to rule OC. This is an important consideration since combined measurements are not cost-effective. The quality of this evidence is, however, threatened by important gaps related to study design, enrolled populations and analytical issues. For instance, despite the clinical need to prioritize the evaluation of biomarker performance in early stage tumours, sound evidence on this cannot be provided. In addition, results should be cautiously interpreted due to wide differences in the type of employed assays and in adopted diagnostic thresholds for HE4. Comparability among results obtained by different commercially available HE4 assays, together with an objective establishment of analytical goals is essential for the optimal clinical application of this marker. [ABSTRACT FROM PUBLISHER]

The recently released document by the Global Task Force on the “universal” definition of myocardial infarction (MI) recommends a single decision limit for cardiac troponin (cTn) corresponding to the 99th percentile limit of the reference value distribution [99th upper reference limit (URL)] for the diagnosis of patients presenting with suspected MI. However, use of this cut-off concentration posed a problem because most assays do not have the sensitivity to consistently measure cTn in the blood of apparently healthy individuals, with a high proportion of the values being below the method's detection limit. In addition to the influence of assay sensitivity, the 99th URL for cTn can vary depending on the reference population used, and its sample size. A marked difference can also be observed between the 99th URL obtained using plasma vs. that obtained with serum. Finally, some interferences with cTn measurement (e.g., by heterophile antibodies) may become more noticeable using assays that have increased analytical sensitivity that measure lower concentrations of these markers. In conclusion, a number of issues can markedly influence the definition of the 99th URL for cTn, which most clinicians are unaware of and may markedly condition the clinical performance of the test in routine practice. Clin Chem Lab Med 2009;47:1179–82. [ABSTRACT FROM AUTHOR]

Abstract: The recently released document by the Global Task Force on the universal definition of myocardial infarction (MI) has strengthened the role of cardiac troponin increase as the main criterion for MI diagnosis. Despite this pivotal role in clinical decisions, a number of assay-related issues can still markedly affect the test performance in the everyday practice. Regarding imprecision and analytical sensitivity, the performance of commercial assays is variable. Moreover, at least for troponin I, there is a lack of standardization among assay results. Appropriate cut points (99th percentile limit of the reference value distribution and/or 10% CV concentration value) can be established only if the assay performance is known and taken into account. Key characteristics to be defined include characterization by appropriate experimental and statistical protocols of the assay detection limit, total imprecision, and definition of the 99th percentile limit of the reference population. The widespread introduction of cardiac troponin measurements is an undoubted improvement, but some performance differences still exist with commercial assays, which most clinicians are unaware of and may give rise to wrong marker interpretation. [Copyright &y& Elsevier]

It is very important that cardiac biomarkers on which clinically relevant decisions will rest are measured with highly reliable assays. Adequate studies are needed before new methods can be implemented in the laboratory routine, and only well‐documented assays should be considered for clinical use. Therefore, it is critical that, as new biomarkers are proposed, quality specifications are developed. Only after appropriate analytical quality specifications are addressed, the issues pertaining to methodological differences that result in non‐harmonized concentration values, and clinical interpretation of biomarker concentrations will be reconciled. Today, the technology to address many analytic problems is at hand, but commitment on the part of manufacturers and their customers in the laboratory and clinical communities is essential. The design control loop is not closed until the finished in vitro diagnostic system is adequately validated to meet the customer needs, including analytical quality specifications. It is essential to determine the attributes and performance characteristics of relevant competitive systems and their degree of acceptance by clinical laboratories in order to demonstrate that user needs are definitely met. The responsibility of defining and implementing these issues must be a shared responsibility among laboratorians, clinicians, industry, and regulatory agencies on an international front. To date, two sets of quality specifications have been published, one for cardiac troponin assays and one for B‐type natriuretic peptide assays. Both address analytical factors, such as calibrator characterization, antibody specificity, assay sensitivity and imprecision, and interferents, as well as preanalytical factors, such as sample type and stability. It would be ideal if regulatory agencies, such as FDA in the United States, accept these criteria for premarket approval clearance applications. [ABSTRACT FROM AUTHOR]

In 1999 the Centre of Biomedical Research (CRB) in co-operation with the Italian interdisciplinary and intersociety Working Group on Markers of Myocardial Damage proposed a national external quality assurance scheme that was granted in accordance with the UK Clinical Pathology Accreditation Standards in 2001. The scheme, which stresses the importance of educational aspects in quality assurance, was scientifically designed to ensure that it would provide an objective assessment of participants' performance and promote quality improvements to meet the needs of participants. The present paper reports on the data collected in EQA cycles conducted to evaluate improvements in the performance of participants and in related methods. The findings obtained demonstrate that during the 4-year experience the scheme provided opportunities to improve the performance of laboratories and promoted an efficient, more satisfactory approach to analytical aspects. The number of unacceptable performances decreased from 11.6% to 5.6% for troponin I, from 19.5% to 9.0% for myoglobin and from 13.2% to 4.3% for creatine kinase myocardial isoenzyme (CK-MB). During cycles in 2001 and 2002, inter-variability (coefficient of variation, CV%) data for all markers appeared satisfactory and showed a significant improvement (lower than 10%), in particular for procedures automated on Dade Beh- ring Dimension and Beckman Access systems. How- ever, reference values/decisional limits declared by laboratories and those suggested by the manufacturers are not comparable, even within the same diagnostic system. The findings demonstrate that participation in EQA schemes provided an opportunity for participating laboratories to continuously improve the quality of their services. [ABSTRACT FROM AUTHOR]

New biomarkers, such as cardiac troponins, have a major role to play for cost-effective management of individuals with acute chest pain and suspected coronary syndrome, and the laboratory is now poised to assume a vital role in assessing damage and determining prognosis. The redefined biochemical criterion proposed to classify acute coronary syndrome patients presenting with ischemic symptoms as patients with myocardial infarction is heavily predicated on an increased troponin concentration in blood. In an era of evidence-based medicine, we can no longer overlook the diagnostic and prognostic benefits provided by the measurement of these highly sensitive and specific proteins.

This paper presents evidence and suggestions from the IFCC C-SMCD on the use of biochemical markers for the triage diagnosis of acute coronary syndromes. There is general agreement that both 'early' and 'definitive' biochemical markers are necessary and that these assays must be available with a turnaround time of 1 h or less. Currently, myoglobin is the marker that most effectively fits the role as an 'early' marker, whereas 'definitive' markers are cardiac troponins. Since the sensitivity of the initial electrocardiogram is only 50% for detecting myocardial infarction, the use of biochemical markers may significantly contribute to the early diagnosis. New sensitive biochemical markers, particularly the cardiac troponins, are presently the best criterion to detect the presence of small myocardial cell damage. Two decision limits are probably needed for the optimum use of troponins: a low abnormal value suggesting the presence of myocardial damage and a higher value suggesting the diagnosis of myocardial infarction. Additional studies should be performed to establish limits for each commercially available assay. Finally, it is recognized that there is no need for the use of any biochemical marker when the clinical diagnosis is unequivocal, other than for diagnosing reinfarction, estimating the infarct size, and monitoring thrombolytic therapy. [ABSTRACT FROM AUTHOR]

Background: Monitoring of test imprecision is one of the most important quality indicators in clinical laboratories. Imprecision goals should be derived from biological variation. The aim of this study was to evaluate the imprecision of eight tumour biomarker assays routinely measured on the Modular E170 system. Methods: Method coefficient of variations (CVs) were obtained by an appropriate Internal Quality Control programme based on the measurement every working day of a fresh-frozen human serum pool with biomarkers concentrations around the clinical cut-offs. We evaluated data collected along the whole year 2008 (n range: 21-461); monthly CVs and their cumulative means were calculated and compared with corresponding goals. Results: Biomarkers concentration means and average yearly CVs (desirable goals in parentheses) were as follows: α-fetoprotein, 9.6 μg/L, 3.9% (6.0%); CA125, 41.2 U/L, 2.8% (12.4%); CA15.3, 32.7 U/L, 3.1% (3.1%); CA19.9, 35.1 U/L, 2.8% (8.0%); CEA, 7.7 μg/L, 4.3% (6.4%); prostate-specific antigen (PSA), 4.1 μg/L, 4.3% (9.1%); CYFRA 21.1, 2.4 μg/L, 5.7% (11.3%); and ferritin, 64.5 μg/L, 4.0% (7.1%). Conclusions: Our study shows that in routine laboratory practice and over a clinically and analytically relevant time-span, the imprecision of the tumour biomarker measurements on the Roche Modular E170 fulfills desirable goals. For four assays (CA125, CA19.9, PSA and CYFRA 21.1) the optimum CV can even be achieved. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Prognostic value of different serum biomarkers for left ventricular remodelling after ST-elevation myocardial infarction treated with primary percutaneous coronary intervention," by J.A. Urbano-Moral, et al in a 2012 issue.

Background Amongst the newly proposed biomarkers for ovarian cancer, serum human epididymis protein 4 (HE4) shows the greatest potential for clinical use. However, systematic appraisals of its biological characteristics are not available. This study sought to critically revise the available literature on biological and lifestyle factors affecting HE4 concentrations in serum to understand their possible influence on the marker interpretation. Methods A literature search was undertaken on electronic databases and references from retrieved articles. Article results were analyzed by evaluating study design, sample size, statistical approach, employed assay and, when available, by collecting similar information for carbohydrate antigen 125 (CA-125). Results Several factors may influence serum HE4 concentrations. In contrast to CA-125, higher HE4 concentrations are reported in the elderly. Although no variations in HE4 concentrations can be clearly associated to menopausal status, a strong difference in biomarker biological intra-individual variation according to the fertility status is reported. Smoking and renal function can also significantly influence HE4 results. Conclusion The knowledge of factors influencing HE4 concentrations is relevant to promote more adequate interpretative criteria for use of this biomarker in the clinical setting. [ABSTRACT FROM AUTHOR]

Abstract Background The addition of human epididymis protein 4 (HE4) to carbohydrate antigen 125 (CA125) in ovarian cancer (OC) assessment has been proposed. We compared the clinical value of biomarker changes in a prospective series of patients undergoing OC monitoring. Methods We studied 43 patients (79% post-menopausal), followed for 3.5 ± 3.1 years. Serous OC was prevalent (53.5%), with 81.4% of patients diagnosed at late stages. Both cut-offs and reference change values (RCV) were used for assessing significant marker changes. Results The use of cut-offs for CA125 and HE4 interpretation appeared equally fitting the evaluation of disease progression defined according to running guidelines, performing better than RCV criterion. However, both markers were simultaneously over cut-offs only in 46% of samples and changed in agreement in 35% of cases. The inspection of individual longitudinal trends indicated as main causes of disagreement the influence of renal impairment on HE4 concentrations and the more significant rate of decrease of CA125 vs. HE4 concentrations early after treatment. CA125 and HE4 changes according to RCV were not predictive of OC progression. Conclusions CA125 appears the most reliable biomarker for OC monitoring, whereas HE4 contributes additional information only in a minority of cases. Highlights • We compared CA125 and HE4 changes in ovarian cancer monitoring. • The use of cut-offs for CA125 and HE4 interpretation equally fitted the evaluation of disease progression. • CA125 and HE4 in the ovarian cancer follow-up may disagree for renal impairment/response to treatment. [ABSTRACT FROM AUTHOR]

Background Automatic photometric determination of the hemolysis index (HI) on serum and plasma samples is central to detect potential interferences of in vitro hemolysis on laboratory tests. When HI is above an established cut-off for interference, results may suffer from a significant bias and undermine clinical reliability of the test. Despite its undeniable importance for patient safety, the analytical performance of HI estimation is not usually checked in laboratories. Here we evaluated for the first time the random source of measurement uncertainty of HI determination on the two Abbott Architect c16000 platforms in use in our laboratory. Methods From January 2016 to September 2017, we collected data from daily photometric determination of HI on a fresh-frozen serum pool with a predetermined HI value of ~ 100 (corresponding to ~ 1 g/L of free hemoglobin). Monthly and cumulative CVs were calculated. Results During 21 months, 442 and 451 measurements were performed on the two platforms, respectively. Monthly CVs ranged from 0.7% to 2.7% on c16000–1 and from 0.8% to 2.5% on c16000-2, with a between-platform cumulative CV of 1.82% (corresponding to an expanded uncertainty of 3.64%). Mean HI values on the two platforms were just slightly biased (101.3 vs. 103.1, 1.76%), but, due to the high precision of measurements, this difference assumed statistical significance (p < 0.0001). Conclusions Even though no quality specifications are available to date, our study shows that the HI measurement on Architect c16000 platform has nice reproducibility that could be considered in establishing the state of the art of the measurement. [ABSTRACT FROM AUTHOR]

Abstract: Background: Data on the correlations between biomarkers to suggest cost-effective multi-marker (MM) panels predictive for ST-elevation myocardial infarction (STEMI) patients are lacking. We sought to explore the relationship between cardiac troponin I (cTnI), C-reactive protein (CRP), B-type natriuretic peptide (BNP), and chromogranin A (CgA) accounting for biomarkers'' profiles detected within 48h from successful primary percutaneous coronary intervention (PPCI). Methods: In 73 STEMI patients cTnI, CRP, BNP, and CgA were measured before PPCI and 6, 24, and 48h later. STATIS methods generalizing Principal Component Analysis on three-way data sets were employed to extract information about: 1) similarities between patients, 2) contribution of each time of sampling and 3) correlations between biomarkers'' profiles. Results: STEMI patients who underwent successful PPCI emerged to have a homogeneous profile tailored on biomarkers'' evaluation within 48h. Their measurements at 24h contributed the most variability and information both to patients'' and to biomarkers'' profiles. BNP and cTnI were highly correlated and explained the 40.1% of the total variance, whereas CgA resulted independent and explained the 26.3% of the total variance. Conclusions: Markers'' measurements at 24h after PPCI contributed most information to the definition of patients'' profile. BNP and cTnI resulted interchangeable in a MM panel for reporting about the extent of necrosis. [Copyright &y& Elsevier]

Abstract: Objectives: Chromogranin A (CgA) and neuron-specific enolase (NSE) are biomarkers for neuroendocrine tumors. Although the knowledge of their biological variation (BV) is critical, only one study for CgA and no data for NSE are available. We report a definitive assessment of BV components of these biomarkers in the same cohort of subjects by an accurately experimental protocol. Design and methods: We collected five blood specimens from each of 22 healthy volunteers (10 men and 12 women, 23–54years) on the same day every two weeks for two months. Serum specimens were stored at −80°C until analysis and analyzed in a single run in duplicate. Data were analyzed by ANOVA. Results: Serum CgA concentrations were significantly higher for women than for men (P=0.01), whereas no difference was found for NSE. Intra-individual variance was not different between genders for both biomarkers. Within- and between-subject CVs were 16.3% and 33.5% for CgA and 13.6% and 11.5% for NSE, respectively. CgA showed marked individuality, suggesting that the use of population-based reference limits is inadequate for its interpretation. Conversely, the low individuality of NSE allows the use of a single reference interval. Reference change values were 46% for CgA and 39% for NSE. Desirable analytical goals for imprecision, bias, and total error were <8.2%, ±9.3%, and ±22.8% for CgA, and <6.8%, ±4.5%, and ±15.7% for NSE, respectively. Conclusion: In this study, we defined BV components of serum CgA and NSE and derived indices that may improve the clinical use of these biomarkers. [Copyright &y& Elsevier]

Abstract: Background: No information is available on the optimal sampling time to catch the highest increase for biomarkers whose elevation after ST-elevation myocardial infarction (STEMI) is prognostic for adverse events. This study aimed to investigate release kinetics and peak times of cardiac troponin I (cTnI), C-reactive protein (CRP), B-type natriuretic peptide (BNP), chromogranin A (CgA) and cystatin C (CyC) in STEMI patients undergoing primary percutaneous coronary intervention (PPCI). Methods: Blood concentrations of cTnI, CRP, BNP, CgA and CyC were measured before and 6h, 24h, and 48h after PPCI in 84 STEMI patients. The averaged trajectory of marker kinetics was estimated by multivariable regression models adjusted for patient characteristics and orthogonal polynomials were used to describe related releases. Results: From the estimated kinetics cTnI peaked at 10h from symptoms, BNP at 28h and CRP within 30h. CyC concentrations did not change, whereas CgA concentrations increased from 6 to 48h after PPCI. The amount of BNP release was found to be affected by the interaction between gender and age: females<75years had BNP concentrations fourfold higher than males. Conclusions: According to different release kinetics a single blood sampling for measuring all biomarkers is not recommended. [Copyright &y& Elsevier]