Showing papers in "Clinical Chemistry and Laboratory Medicine in 2015"

Defining analytical performance specifications: Consensus Statement from the 1st Strategic Conference of the European Federation of Clinical Chemistry and Laboratory Medicine

Abstract: *Corresponding author: Sverre Sandberg, Norwegian Quality Improvement of Primary Care Laboratories (Noklus), Institute of Global Public Health and Primary Health Care, University of Bergen and Laboratory of Clinical Biochemistry, Bergen, Norway, E-mail: sverre.sandberg@isf.uib.no Callum G. Fraser: Centre for Research into Cancer Prevention and Screening, University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland, UK Andrea Rita Horvath: SEALS Department of Clinical Chemistry, Prince of Wales Hospital, Screening and Test Evaluation Program, School of Public Health, University of Sydney, and School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia Rob Jansen: Netherlands Foundation for Quality Assessment of Medical Laboratories (SKML), Radboud University, Nijmegen, The Netherlands Graham Jones: SydPath, St Vincent’s Hospital, Sydney, NSW, Australia Wytze Oosterhuis: Atrium-Orbis, Department of Clinical Chemistry and Haematology, Heerlen, The Netherlands Per Hyltoft Petersen: Norwegian Quality Improvement of Primary Care Laboratories (Noklus), Institute of Global Public Health and Primary Health Care, University of Bergen, Norway Heinz Schimmel: European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Geel, Belgium Ken Sikaris: Sonic Healthcare and Melbourne University, Melbourne, Vic, Australia Mauro Panteghini: Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy Consensus Statement

Combined indicator of vitamin B12 status: modification for missing biomarkers and folate status and recommendations for revised cut-points.

Abstract: BACKGROUND A novel approach to determine vitamin B12 status is to combine four blood markers: total B12 (B12), holotranscobalamin (holoTC), methylmalonic acid (MMA) and total homocysteine (tHcy). This combined indicator of B12 status is expressed as cB12=log10[(holoTC·B12)/(MMA·Hcy)]-(age factor). Here we calculate cB12 in datasets with missing biomarkers, examine the influence of folate status, and revise diagnostic cut-points. METHODS We used a database with all four markers (n=5211) plus folate measurements (n=972). A biomarker Z (assumed missing) was plotted versus X (a combination of other markers) and Y (age). Each chart was approximated by a function Ztheor, which predicted the potentially absent value(s). Statistical distributions of cB12 were aligned with physiological indicators of deficiency and used to determine cut-offs. RESULTS The predictive functions Ztheor allowed assessment of the "incomplete" indicators, 3cB12 (three markers known) and 2cB12 (two markers known). Predictions contained a systematic deviation associated with dispersion along two axes Z and X (and unaccounted by the least squares fit). Increase in tHcy at low serum folate was corrected (cB12+Δfolate) based on the function of Δfolate=log10(Hcyreal/Hcytheor) versus folate. Statistical distributions of cB12 revealed the boundaries of groups with B12 deficiency, i.e., cB12<-0.5. CONCLUSIONS We provide equations that combine two, three or four biomarkers into one diagnostic indicator, thereby rescaling unmatched data into the same coordinate system. Adjustment of this indicator is required if serum folate is <10 nmol/L and tHcy is measured. Revised cut-points and guidelines for using this approach are provided.

Performance criteria and quality indicators for the post-analytical phase.

Abstract: The definition, implementation and monitoring of valuable analytical quality specifications have played a fundamental role in improving the quality of laboratory services and reducing the rates of analytical errors. However, a body of evidence has been accumulated on the relevance of the extra-analytical phases, namely the pre-analytical steps, their vulnerability and impact on the overall quality of the laboratory information. The identification and establishment of valueable quality indicators (QIs) represents a promising strategy for collecting data on quality in the total testing process (TTP) and, particularly, for detecting any mistakes made in the individual steps of the pre-analytical phase, thus providing useful information for quality improvement projects. The consensus achieved on the developed list of harmonized QIs is a premise for the further step: the identification of achievable and realistic performance targets based on the knowledge of the state-of-the-art. Data collected by several clinical laboratories worldwide allow the classification of performances for available QIs into three levels: optimum, desirable and minimum, in agreement with the widely accepted proposal for analytical quality specifications.

A checklist for critical appraisal of studies of biological variation.

Abstract: Data on biological variation are used for many purposes in laboratory medicine but concern exists over the validity of the data reported in some studies. A critical appraisal checklist has been produced by a working group established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) to enable standardised assessment of existing and future publications of biological variation data. The checklist identifies key elements to be reported in studies to enable safe accurate and effective transport of biological variation data sets across healthcare systems. The checklist is mapped to the domains of a minimum data set required to enable this process.

Role of leptin in female reproduction

Abstract: Reproductive function is dependent on energy resources. The role of weight, body composition, fat distribution and the effect of diet have been largely investigated in experimental female animals as well as in women. Any alteration in diet and/or weight may induce abnormalities in timing of sexual maturation and fertility. However, the cellular mechanisms involved in the fine coordination of energy balance and reproduction are largely unknown. The brain and hypothalamic structures receive endocrine and/or metabolic signals providing information on the nutritional status and the degree of fat stores. Adipose tissue acts both as a store of energy and as an active endocrine organ, secreting a large number of biologically important molecules termed adipokines. Adipokines have been shown to be involved in regulation of the reproductive functions. The first adipokine described was leptin. Extensive research over the last 10 years has shown that leptin is not only an adipose tissue-derived messenger of the amount of energy stores to the brain, but also a crucial hormone/cytokine for a number of diverse physiological processes, such as inflammation, angiogenesis, hematopoiesis, immune function, and most importantly, reproduction. Leptin plays an integral role in the normal physiology of the reproductive system with complex interactions at all levels of the hypothalamic-pituitary gonadal (HPG) axis. In addition, leptin is also produced by placenta, where it plays an important autocrine function. Observational studies have demonstrated that states of leptin excess, deficiency, or resistance can be associated with abnormal reproductive function. This review focuses on the leptin action in female reproduction.

Preanalytical quality improvement. In pursuit of harmony, on behalf of European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working group for Preanalytical Phase (WG-PRE)

Abstract: Laboratory diagnostics develop through different phases that span from test ordering (pre-preanalytical phase), collection of diagnostic specimens (preanalytical phase), sample analysis (analytical phase), results reporting (postanalytical phase) and interpretation (post-postanalytical phase). Although laboratory medicine seems less vulnerable than other clinical and diagnostic areas, the chance of errors is not negligible and may adversely impact on quality of testing and patient safety. This article, which continues a biennial tradition of collective papers on preanalytical quality improvement, is aimed to provide further contributions for pursuing quality and harmony in the preanalytical phase, and is a synopsis of lectures of the third European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)-Becton Dickinson (BD) European Conference on Preanalytical Phase meeting entitled 'Preanalytical quality improvement. In pursuit of harmony' (Porto, 20-21 March 2015). The leading topics that will be discussed include unnecessary laboratory testing, management of test request, implementation of the European Union (EU) Directive on needlestick injury prevention, harmonization of fasting requirements for blood sampling, influence of physical activity and medical contrast media on in vitro diagnostic testing, recent evidence about the possible lack of necessity of the order of draw, the best practice for monitoring conditions of time and temperature during sample transportation, along with description of problems emerging from inappropriate sample centrifugation. In the final part, the article includes recent updates about preanalytical quality indicators, the feasibility of an External Quality Assessment Scheme (EQAS) for the preanalytical phase, the results of the 2nd EFLM WG-PRE survey, as well as specific notions about the evidence-based quality management of the preanalytical phase.

High sensitivity cardiac troponin assays in the clinical laboratories

Abstract: Immunoassays measuring cardiac troponins I or T have become firmly established as critical tools for diagnosing acute myocardial infarction. While most contemporary assays provide adequate diagnostic performance, the increased sensitivity and precision of the new, high sensitivity assays that have already been introduced into clinical practice, provide the potential to further shorten intervals between blood draws or the time needed to detect the first significant troponin elevation. In addition to the relatively modest benefits at the diagnostic end, the high sensitivity assays and the investigational ultrasensitive cardiac troponin assays offer improvements for predicting major adverse cardiovascular events, development of heart failure or transition to end-stage kidney disease. These novel high sensitivity assays can measure troponin concentrations in 50%-100% of healthy individuals and therefore allow for the distribution of troponin values within a healthy cohort to be measured, patient's baseline troponin levels to be monitored, and clinicians to be alerted of deteriorating cardiorenal conditions. We envisage that the high sensitivity assays will become important tools for predicting each patient's risk of future adverse events and for guiding and monitoring corresponding adjustments of preventative therapeutic interventions.

Recent guidelines and recommendations for laboratory assessment of the direct oral anticoagulants (DOACs): is there consensus?

Abstract: A new generation of antithrombotic agents, which are conventionally known as direct oral anticoagulants (DOACs), have recently emerged and are continuing to be developed. These provide direct inhibition of either thrombin (factor IIa; FIIa) or activated factor X (FXa) and currently include dabigatran (FIIa inhibitor) and rivaroxaban, apixaban, and edoxaban (FXa inhibitors). The dogma that DOACs do not require laboratory monitoring is countered by ongoing recognition that laboratory testing for drug effects is needed in many situations. In this review, we summarize the background to establishment of DOACs, assess which tests were found to be useful to screen for or quantitate drug effects/levels, and then review published guidelines/recommendations to assess concordance. In brief, (a) for the anti-FIIa agent dabigatran, the recommended screening assays are activated partial thromboplastin time (APTT) and/or thrombin time (TT), and the quantitative assays (using a dabigatran standard) are dilute TT/direct thrombin inhibitor assay (Hemoclot thrombin inhibitor) or an ecarin-based assay such as the ecarin clot time (ECT); (b) for the anti-FXa agent rivaroxaban, the recommended screening assay is the prothrombin time (PT), but this was not endorsed by all guidelines, and the quantitative assay (using a specific rivaroxaban standard) is an anti-FXa assay; (c) for the anti-FXa agent apixaban, the general insensitivity of PT and APTT prevented most groups from providing recommendation, and instead there was generalized support for direct quantitative assessment using anti-FXa assays and specific apixaban standard; (d) there is insufficient data for other direct anti-FXa agents and limited guidance in the literature.

Biological variation database: structure and criteria used for generation and update

Abstract: Background Numerical data on the components of biological variation (BV) have many uses in laboratory medicine, including in the setting of analytical quality specifications, generation of reference change values and assessment of the utility of conventional reference values. Methods Generation of a series of up-to-date comprehensive database of components of BV was initiated in 1997, integrating the more relevant information found in publications concerning BV. A scoring system was designed to evaluate the robustness of the data included. The database has been updated every 2 years, made available on the Internet and derived analytical quality specifications for imprecision, bias and total allowable error included in the tabulation of data. Results and conclusions Our aim here is to document, in detail, the methodology we used to evaluate the reliability of the included data compiled from the published literature. To date, our approach has not been explicitly documented, although the principles have been presented at many symposia, courses and conferences.

A review of the cut-off points for the diagnosis of vitamin B12 deficiency in the general population

Abstract: Vitamin B12 deficit is one of the most common vitamin deficiencies. However, there is no consensus on the cut-off points for vitamin B12 and its co-markers, such as folate, holotranscobalamin, methylmalonic acid and homocysteine. In order to establish the state of the art about cut-off points used to determine vitamin B12 deficiency in the last decades, the database MEDLINE was used for searching studies published in adults between December 1992 and May 2014 (69 articles), using search terms like 'vitamin B12', 'cobalamin', 'cut-off', 'deficiency' alone or in combinations. Broad ranges of cut-off points for vitamin B12 and its biomarkers were identified: vitamin B12 ranged between 100 pmol/L and 350 pmol/L, holotranscobalamin 20-50 pmol/L, methylmalonic acid 0.210-0.470 μmol/L, homocysteine 10-21.6 μmol/L, serum folate 3.7-15.9 nmol/L and red blood cell 124-397 nmol/L. For the majority of studies, the potential influence of age, analytical methods, gender and fortified food consumption was not taken in account when choosing cut-off values. This could explain the discrepancies between studies on vitamin B12 and folate deficiency prevalences. We conclude that there is inconsistency in the literature regarding vitamin B12 cut-offs. It would be necessary to establish different reference cut-offs according to age, considering the analytical methods used.

Discriminant indices for distinguishing thalassemia and iron deficiency in patients with microcytic anemia: a reply

Abstract: Background More than 40 mathematical indices have been proposed in the hematological literature for discriminating between iron deficiency anemia and thalassemia trait in subjects with microcytic red blood cells (RBCs). None of these discriminant indices is 100% sensitive and specific and also the ranking of the discriminant indices is not consistent. Therefore, we decided to conduct the first meta-analysis of the most frequently used discriminant indices. Methods An extensive literature search yielded 99 articles dealing with 12 indices that were investigated five or more times. For each discriminant index we calculated the diagnostic odds ratio (DOR) and summary ROC analysis was done for comparing the performance of the indices. Results The ratio of microcytic to hypochromic RBCs (M/H ratio) showed the best performance, DOR=100.8. This was significantly higher than that of all other indices investigated. The RBC index scored second (DOR=47.0), closely followed by the Sirdah index (DOR=46.7) and the Ehsani index (DOR=44.7). Subsequently, there was a group of four indices with intermediate and three with lower DOR. The lowest performance (DOR=6.8) was found for the RDW (Bessman index). Overall, the indices performed better for adults than for children. Conclusions The M/H ratio outperformed all other discriminant indices for discriminating between iron deficiency anemia and thalassemia trait. Although its sensitivity and specificity are not high enough for making a definitive diagnosis, it is certainly of value for identifying those subjects with microcytic RBC in whom diagnostic tests for confirming thalassemia are indicated.

Effect of age and gender on reference intervals of red blood cell distribution width (RDW) and mean red cell volume (MCV).

Abstract: Background Red blood cell distribution width (RDW) was recently shown to be age-dependent when using Sysmex XE-2100 hematology analyzers. As measuring RDW is subject to technology, we have investigated if this relation also exists when using a different hematology analyzer, Abbott CELL-DYN Sapphire. In addition, as RDW is generally expressed relative to mean red blood cell volume (MCV), we have explored how MCV influences the age-dependency of RDW. Methods We measured RDW and MCV in a large cohort and calculated RDW-SD (the "absolute" RDW), which does not contain MCV. For establishing reference intervals we used Bhattacharya statistics. Results In our study cohort of 8089 individuals we found a strong association between RDW and age, but not with gender. Also MCV showed an age-related increase over the entire age range. The conventional RDW increased by 6% from the youngest to oldest age class, whereas RDW-SD increased by nearly 15%. This difference was caused by a mean age-related increase in MCV of 6.6%. Age-dependent reference intervals were established for RDW, RDW-SD and MCV. Conclusions The age-dependency of RDW seems to be a universal biological feature rather than related with a single type of hematology analyzer. As not only RDW, but also MCV increases with age, we propose that future studies on the prognostic significance of RDW take its age-dependency into account and focus on RDW-SD as a potential marker of adverse events in many clinical conditions.

Influence of educational, audit and feedback, system based, and incentive and penalty interventions to reduce laboratory test utilization: a systematic review

Abstract: Laboratory and radiographic tests are often ordered unnecessarily. This excess testing has financial costs and is a burden on patients. We performed a systematic review to determine the effectiveness interventions to reduce test utilization by physicians. The MEDLINE and EMBASE databases were searched for the years 1946 through to September 2013 for English articles that had themes of test utilization and cost containment or optimization. Bibliographies of included papers were scanned to identify other potentially relevant studies. Our search resulted in 3236 articles of which 109 met the inclusion criteria of having an intervention aimed at reducing test utilization with results that could be expressed as a percent reduction in test use relative to the comparator. Each intervention was categorized into one or more non-exclusive category of education, audit and feedback, system based, or incentive or penalty. A rating of study quality was also performed. The percent reductions in test use ranged from a 99.7% reduction to a 27.7% increase in test use. Each category of intervention was effective in reducing test utilization. Heterogeneity between interventions, poor study quality, and limited time horizons makes generalizations difficult and calls into question the validity of results. Very few studies measure any patient safety or quality of care outcomes affected by reduced test use. There are numerous studies that use low investment strategies to reduce test utilization with one time changes in the ordering system. These low investment strategies are the most promising for achievable and durable reductions in inappropriate test use.

Compliance of blood sampling procedures with the CLSI H3-A6 guidelines: An observational study by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) working group for the preanalytical phase (WG-PRE).

Abstract: Background: An observational study was conducted in 12 European countries by the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for the Preanalytical Phase (EFLM WG ...

Utility of procalcitonin, C-reactive protein and white blood cells alone and in combination for the prediction of clinical outcomes in community- acquired pneumonia

Abstract: Background: The added value of biomarkers, such as procalcitonin (PCT), C-reactive protein (CRP), and white blood cells (WBC), as adjuncts to clinical risk scores for predicting the outcome of patients with communityacquired pneumonia (CAP) is in question. We investigated the prognostic accuracy of initial and follow-up levels of inflammatory biomarkers in predicting death and adverse clinical outcomes in a large and well-defined cohort of CAP patients. Methods: We measured PCT, CRP and WBC on days 1, 3, 5, and 7 and followed the patients over 30 days. We applied multivariate regression models and area under the curve (AUC) to investigate associations between these biomarkers, the clinical risk score CURB-65, and clinical outcomes [i.e., death and intensive care unit (ICU) admission]. Results: Of 925 patients with CAP, 50 patients died and 118 patients had an adverse clinical outcome. None of the initial biomarker levels significantly improved the CURB-65 score for mortality prediction. Follow-up biomarker levels showed significant independent association with mortality at days 3, 5, and 7 and with improvements in AUC. Initial PCT and CRP levels were independent prognostic predictors of adverse clinical outcome, and levels of all biomarkers during the course of disease provided additional prognostic information. Conclusions: This study provides robust insights into the added prognostic value of inflammatory markers in CAP. Procalcitonin, CRP, and to a lesser degree WBC provided some prognostic information on CAP outcomes, particularly when considering their kinetics at days 5 and 7 and when looking at adverse clinical outcomes instead of mortality alone.

Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden

Abstract: Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmo creatinine and CAPA cystatin C equations (MEAN(LM-REV+CAPA)), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEAN(CKD-EPI)), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine. Methods: The study included 1200 examinations in 1112 adult Swedish patients referred for measurement of GFR (mGFR) 2008-2010 by plasma clearance of iohexol (median 51 mL/min/1.73 m(2)). Bias, precision (interquartile range, IQR) and accuracy (percentage of estimates +/- 30% of mGFR; P-30) were compared. Results: Combined marker equations were unbiased and had higher precision and accuracy than single marker equations. Overall results of MEAN(LM-REV+CAPA)/MEAN(CKD-EPI)/CKD-EPICREA+CYSC were: median bias -2.2%/-0.5%/-1.6%, IQR 9.2/9.2/8.8 mL/min/1.73 m(2), and P-30 91.3%/91.0%/91.1%. The P-30 figures were about 7-14 -percentage points higher than the single marker equations. The combined equations also had a more stable performance across mGFR, age and BMI intervals, generally with P-30 >= 90% and never = 40%. Conclusions: Combining cystatin C and creatinine assays improves GFR estimations with P-30 >= 90% in adults. Reporting estimates of both single and combined marker equations in clinical settings makes it possible to assess the validity of the combined equation based on the agreement between the single marker equations. (Less)

Quantification of piperacillin, tazobactam, cefepime, meropenem, ciprofloxacin and linezolid in serum using an isotope dilution UHPLC-MS/MS method with semi-automated sample preparation.

Abstract: BACKGROUND Recent studies have demonstrated highly variable blood concentrations of piperacillin, tazobactam, cefepime, meropenem, ciprofloxacin and linezolid in critically ill patients with a high incidence of sub-therapeutic levels. Consequently, therapeutic drug monitoring (TDM) of these antibiotics has to be considered, requiring robust and reliable routine analytical methods. The aim of the present work was to develop and validate a multi-analyte ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous quantification of the above mentioned antibiotics. METHODS Sample preparation included a manual protein precipitation step followed by two-dimensional ultra high performance liquid chromatography (2D-UHPLC). Corresponding stable isotope-labeled substances were used as internal standards for all of the analytes, with the exception of tazobactam. The injected sample volume was 7 μL. The run time was 5.0 min. RESULTS Inaccuracy was ≤8% and imprecision coefficient of variation (CV) was <9% for all analytes. Only minor matrix effects and negligible carry-over was observed. The method was found to be robust during the validation period. CONCLUSIONS We were able to develop a reliable 2D-UHPLC-MS/MS method addressing analytes with highly heterogeneous physico-chemical properties. The novel assay may be an efficient tool for an optimized process workflow in clinical laboratories for important antibiotics in regards to TDM.

High-sensitivity cardiac troponin I in the general population – defining reference populations for the determination of the 99th percentile in the Gutenberg Health Study

Abstract: Background The 99th percentile of cardiac troponin levels, determined in a reference population, is accepted as threshold for diagnosis of acute myocardial infarction (AMI). However, there is no common consensus of how to define the reference population. The aim of the present study was to determine 99th percentile reference values, determined by a high-sensitivity assay (hsTnI), according to different health status and cardiovascular risk factor prevalence in a large population-based sample. Methods Troponin I was determined using the Abbott ARCHITECT STAT highly sensitive troponin I immunoassay in 4138 participants of the Gutenberg Health Study. Results hsTnI was detectable in 81.6% of all individuals. The 99th percentile of the overall population was 27 ng/L. Age and gender had a prominent influence on these values. Exclusion of individuals with elevated natriuretic peptide levels or cardiac abnormalities resulted in lower 99th percentile values, whereas exclusion of individuals with an impaired estimated glomerular filtration rate (eGFR) or with prevalent coronary artery disease/myocardial infarction (CAD/MI) did not result in a meaningful change. Conclusions Troponin I, measured by a high-sensitivity assay, can be reliably detected in the vast majority of the general population. hsTnI values were dependent on age, gender as well as structural and functional cardiac abnormalities.

Economic evaluation of procalcitonin-guided antibiotic therapy in acute respiratory infections: a US health system perspective

Abstract: Clin Chem Lab Med 2015; aop*Corresponding author: John E. Schneider, PhD, CEO, Avalon Health Economics, 20 South Street, Suite 2B; Morristown, NJ 07960, USA, Phone: + 1 862 260 9191, E-mail: John.Schneider@avalonecon.com Philipp Schuetz, Alexander Kutz and Beat Mueller: University Department of Medicine, Kantonsspital Aarau, Aarau, Switzerland Robert Balk: Pulmonary and Critical Care Medicine, Rush University Medical Center, 1653 W. Congress Parkway, Chicago, IL, USA Matthias Briel and Heiner C. Bucher: BaselInstitute for Clinical Epidemiology and Biostatistics, University Hospital Basel, Basel, Switzerland Mirjam Christ-Crain and Neera Bhatnagar: Division of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Basel, Basel, Switzerland Daiana Stolz and Michael Tamm: ClinicofPneumologyand Pulmonary Cell Research, University Hospital Basel, Basel, Switzerland Lila Bouadma and Michel Wolff: Service de R e animation M e dicale, Universit e Paris 7-Denis-Diderot, H o pitBichal at-Claude-Bernard, Assistance Publique-H o pitaux de Paris (AP-HP), Paris, France Kristina B. Kristoffersen: Deparmentt ofInfectious Diseases, Aarhus, University Hospital, Skejby, Aarhus, Denmark Long Wei: Department of Internal and Geriatrics Medicine, Shanghai Jiao Tong University Affiliated Sixth People ’ s Hospital, Shanghai, P.R. China Olaf Burkhardt and Tobias Welte: Medizinische Hochschule Hannover, Department of Pulmonary Medicine, Hannover, Germany Stefan Schroeder: Department of Anesthesiology and Intensive Care Medicine, Krankenhaus Dueren, Dueren, Germany Vandack Nobre: Intensive Care, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil Matthias Briel: Deparmentt ofClinicalEpidemiologyand Biostatistics, McMaster University, Hamilton, Canada Charles-Edouard Luyt and Jean Chastre: Service de R e animation M e dicale, Universit e Paris 6-Pierre-et-Marie-Cie, ur H o pitPiti e -alSalp e ti e re, r AP-HP, Paris, France Florence Tubach: AP-HP, H o pitauxUniversitaires Paris Nordde V alSeine, D e partementd ’ Epid e miologie Biostatistique etRecherche Clinique, Paris, France, Universit e Paris Diderot, Sorbonne Paris Cit e , UMR 738, Paris, France INSERM, UMR 738, Paris, France INSERM, CIE801, Paris, France Michael J. Lacey, Robert L. Ohsfeldt and Cara M. Scheibling: Avalon Health Economics, 20 South Street, Suite 2B, Morristown, NJ, USA

The lymphocyte to monocyte ratio in peripheral blood represents a novel prognostic marker in patients with pancreatic cancer

Abstract: BACKGROUND Intra-tumoral macrophages have been involved as important players in the pathogenesis and progression of cancer. Recently, inflammatory parameters of the systemic inflammatory response have also been proposed as usefully prognostic biomarkers. One of these, the lymphocyte to monocyte ratio (LMR) in peripheral blood has been shown as a prognostic factor in hematologic and some solid tumors. In this study we analyzed for the first time the prognostic value of LMR in a large middle European cohort of pancreatic cancer (PC) patients. METHODS Data from 474 consecutive patients with ductal adenocarcinoma of the pancreas were evaluated retrospectively. Cancer-specific survival (CSS) was analyzed using the Kaplan-Meier method. To further evaluate the prognostic significance of the LMR, univariate and multivariate Cox regression models were calculated. RESULTS Increased LMR at diagnosis was significantly associated with well-established prognostic factors, including high tumor stage and tumor grade (p<0.05). In univariate analysis, we observed that an increased LMR was a significant factor for better CSS in PC patients (HR 0.70; 95% CI 0.57-0.85; p<0.001). In multivariate analysis including age, Karnofsky Index, tumor grade, tumor stage, administration of chemotherapy, LMR and surgical resection, we confirmed increased LMR as an independent prognostic factor for CSS (HR 0.81; 95% CI 0.66-0.99; p=0.04). CONCLUSIONS In conclusion, we identified LMR as an independent prognostic factor in PC patients. Our results indicate that the LMR might represent a novel and useful marker for patient stratification in PC management.

Comparison of five automated hematology analyzers in a university hospital setting: Abbott Cell-Dyn Sapphire, Beckman Coulter DxH 800, Siemens Advia 2120i, Sysmex XE-5000, and Sysmex XN-2000

Abstract: Background Various types of automated hematology analyzers are used in clinical laboratories. Here, we performed a side-by-side comparison of five current top of the range routine hematology analyzers in the setting of a university hospital central laboratory. Methods Complete blood counts (CBC), differentials, reticulocyte and nucleated red blood cell (NRBC) counts of 349 patient samples, randomly taken out of routine diagnostics, were analyzed with Cell-Dyn Sapphire (Abbott), DxH 800 (Beckman Coulter), Advia 2120i (Siemens), XE-5000 and XN-2000 (Sysmex). Inter-instrument comparison of CBCs including reticulocyte and NRBC counts and investigation of flagging quality in relation to microscopy were performed with the complete set of samples. Inter-instrument comparison of five-part differential was performed using samples without atypical cells in blood smear (n=292). Automated five-part differentials and NRBCs were additionally compared with microscopy. Results The five analyzers showed a good concordance for basic blood count parameters. Correlations between instruments were less well for reticulocyte counts, NRBCs, and differentials. The poorest concordance for NRBCs with microscopy was observed for Advia 2120i (Kendall's τb=0.37). The highest flagging sensitivity for blasts was observed for XN-2000 (97% compared to 65%-76% for other analyzers), whereas overall specificity was comparable between different instruments. Conclusions To the best of our knowledge, this is the most comprehensive side-by-side comparison of five current top of the range routine hematology analyzers. Variable analyzer quality and parameter specific limitations must be considered in defining laboratory algorithms in clinical practice.

Influence of storage conditions and extraction methods on the quantity and quality of circulating cell-free DNA (ccfDNA): the SPIDIA-DNAplas External Quality Assessment experience

Abstract: Background Circulating cell-free DNA (ccfDNA) has been confirmed as a useful biomarker in cancer and pre-natal clinical practice. One of the main critical points in using ccfDNA is a lack of standardisation for sample processing methods, storage conditions, procedures for extraction, and quantification that can affect ccfDNA quality and quantity. We report the results obtained from the SPIDIA-DNAplas, one of the EU SPIDIA (Standardisation and improvement of generic pre-analytical tools and procedures for in vitro diagnostics) subprojects based on the implementation of an External Quality Assessment scheme for the evaluation of the influence of the pre-analytical phase on ccfDNA. This is the first reported quality control scheme targeting ccfDNA for pre-analytical phase studies. Methods Fifty-six laboratories throughout Europe were recruited. The participating laboratories received the same plasma sample and extracted ccfDNA by using their own procedures, at defined plasma storage conditions, and sent the isolated ccfDNA to the SPIDIA facility for analyses. Laboratory performance was evaluated by using specific quality parameters such as ccfDNA integrity (by multiplex PCR) and yield (by qPCR). Results The analysis of the ccfDNA extracted by the laboratories showed that most of them (53 of 56) were able to recover ccfDNA but only 12.5% recovered non-fragmented ccfDNA. Extraction methods specifically designed for ccfDNA preserved the integrity profile. Conclusions The evidence-based results of the SPIDIA-DNAplas EQA have been proposed as a basis for the development of a Technical Specification by the European Committee for standardisation (CEN).

Reliability of biological variation data available in an online database: need for improvement.

Abstract: Background Biological variation (BV) data enable assessment of the significance of changes in serial measurements observed within a subject and are used to set analytical quality specifications. This data is available in a database held in Westgard website (http://www.westgard.com/biodatabase1.htm). Some limitations of this data, however, have been identified in recent published reviews. The aim of this paper is to show the reliability of the published BV data and to identify ongoing works to address some of its limitations. Methods The BV data currently hosted on the Westgard website was examined. Distribution of measurands stratified by the number of cited references upon which the database entry is based and the distribution of papers stratified by publication year, are shown. Moreover, BV data available in literature for glycated hemoglobin, C-reactive protein, glycated albumin, alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transferase are evaluated. Results The results obtained show that most BV data come just from a few papers or only one paper and that a lot of publications are dated, therefore this data is too obsolete to be used. Furthermore critical review of the BV database highlights a number of factors that might impact on the reliability of the BV data entries and translation into current practice. Conclusions A number of issues clearly undermine the value of the current database. These issues are being considered by the European Federation of Clinical Chemistry and Laboratory Medicine, biological variation working group, in collaboration with a Spanish group responsible for the database updating.

Serum calcitonin negative medullary thyroid carcinoma: a systematic review of the literature

Abstract: Generally, calcitonin (CT) values below the upper reference limit rule-out medullary thyroid carcinoma (MTC) with very high accuracy. However, sparse cases of serum-calcitonin-negative MTC (CT-NEG-MTC) have been reported. Here we reviewed CT-NEG-MTC reported in liter- ature, discussed the potential causes and proposed a prac- tical laboratory and clinical approach. A comprehensive literature search was conducted by using the terms " med- ullary thyroid carcinoma " AND " non-secreting calcitonin " OR " undetectable calcitonin " . The search was updated until December 2014. Original articles that described CT- NEG-MTC were eligible for inclusion. Only MTC cases with preoperative CT below the upper reference limit were included in the present review. Eleven papers with 18 CT- NEG-MTC cases (age 50 years, size 26 mm) were retrieved. Four patients with poorly differentiated MTC died within 3 years. Different CT assays were employed and different reference values were adopted. Preoperative serum CT val- ues were below the institution cut-off levels in all cases, and undetectable in four patients. In some papers nega- tive CT results were confirmed by additional tests. Further laboratory investigations were performed in some of the included studies. In patients with well founded suspi- cious of MTC and within the reference limits/undetecta- ble CT other laboratory investigations (carcinoembryonic antigen (CEA), procalcitonin, CT stimulation, CT in wash- out of nodule ' s aspiration) have to be performed. Surgi- cal approach to CT-NEG-MTC does not differ from those secreting CT. Postoperative follow-up of these rare cases should include periodical imaging and measurement of all potential markers. Patients with poorly differenti- ated MTC are at higher risk of disease-related death, and require more aggressive follow-up strategy.

Defining analytical performance specifications 15 years after the Stockholm conference.

Abstract: The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has as part of its mission “to be the leading organization of Laboratory Medicine in Europe.” Through leadership, the EFLM strives to enhance patient care and improve outcomes by promoting and improving the scientific, professional and clinical aspects of laboratory medicine. To focus on important aspects in laboratory medicine in which some strategic actions and measures should be taken, the EFLM decided to start a biannual series of conferences. The first edition was held in Milan, Italy, on November 2014. The conference was entitled “Defining analytical performance goals 15 years after the Stockholm conference” as it was considered timely to address the topic of performance specifications both because it was a long time since it was previously addressed and because performance specifications are central for the clinical application of test measurements and are also of vital importance for quality control measures that should be taken in the laboratories. The conference, organized in cooperation with the Centre for Metrological Traceability in Laboratory Medicine (CIRME) of the University of Milan and the Institute for Reference Materials and Measurements (IRMM) of the European CommissionJoint Research Centre, was very successful, with 215 participants from 41 different countries, embracing the five continents (the complete list of conference participants is available as electronic Supplementary Material that accompanies the article at http://www.degruyter. com/view/j/cclm.2015.53.issue-6/cclm-2015-0303/cclm2015-0303.xml?format=INT). The delegates came from clinical laboratories, from EQAS providers and other professional organizations as well as from the in vitro diagnostics (IVD) manufacturers. In this issue of Clinical Chemistry and Laboratory Medicine all contributions given during the conference are published (the slides of presentations are available online at http://www.efcclm. eu/index.php/educational-material.html). The Stockholm Conference in 1999 was a landmark in trying to achieve a consensus on how quality specifications should be set and a hierarchy of models was established [1]. In his paper, Callum Fraser gives not only a historic review of the 1999 Conference, where he served as a cochair, but also a general survey of the history of laboratory quality specifications [2]. He underlines that time has come to revisit this hierarchy, investigating to what extent it is still valid or if it should be modified or expanded, which is the ultimate goal of the EFLM conference. The conference comprised five sessions. The first three sessions examined the possibility and the pros and cons to base performance specifications on clinical needs, on biological variation data or on state-of-the-art of the measurement procedure, respectively. In their article on behalf of the EFLM Working Group (WG) on Test Evaluation, Horvath et al. [3] discuss the complexity of outcomerelated models in a way that allows investigation of the impact of analytical performance on medical decisions and patient management. Whilst it is acknowledged that these types of evaluations are difficult and may not be possible for all measurands in laboratory medicine, the authors consider this approach as the “gold standard” for setting specifications. Next, Per Hyltoft Petersen, another one of the 1999 conference organizers, expanded the discussion to cover the use of simulation studies as a way to model the probability of clinical outcome and the impact of analytical performance upon them [4]. As an example, the influence of analytical performance is investigated for diagnosing of diabetes using hemoglobin A1c and for individuals at risk for coronary heart disease as defined by serum cholesterol concentrations. In another article, Thue and Sandberg address the topic of performance specifications based on how clinicians use laboratory tests [5]. These authors comment, however, that there is a large variability among clinician behaviors that can limit the role of this approach and that it merely reflects the expectations of the clinicians rather than the ultimate specifications that should be set. The group of Ricos reviews the rationale for using data on biological variation to derive analytical specifications

Matrix metalloproteinases as biomarkers of disease: updates and new insights

Abstract: Matrix metalloproteinases (MMPs) play a pivotal role in remodeling the extracellular matrix (ECM) and are therefore of interest for new diagnostic tools for the clinical management of diseases involving ECM disruption. This setting ranges from the classical areas of MMP studies, such as vascular disease, cancer progression or bone disorders, to new emerging fields of application, such as neurodegenerative disease or sepsis. Increasing the knowledge about the role of MMPs in the pathogenesis of diseases where a clear diagnostic panel is still lacking could provide new insight and improve the identification and the clinical treatment of these human diseases. This review focuses on the latest descriptions of the clinical use of MMP as biomarkers in the diagnosis, prognosis and monitoring of different diseases, such as diabetes, cardiovascular diseases, cancer and metastasis, neurodegenerative disorders and sepsis.

Diagnosis and evaluation of severity of sepsis via the use of biomarkers and profiles of 13 cytokines: a multiplex analysis.

Abstract: Background The object of this study was to evaluate biomarkers for diagnosis of sepsis, hematologic parameters, and cytokine profiles for use in the diagnosis and evaluation of severity of sepsis. Methods We enrolled 127 consecutive patients with systemic inflammatory response syndrome (SIRS), 97 of whom were diagnosed with sepsis. The following biomarkers were evaluated: procalcitonin (PCT); C-reactive protein (CRP); erythrocyte sedimentation rate (ESR); white blood cell count, immature granulocyte (IG) count; and multiplex cytokines, including interleukin (IL)1-β (IL1β), IL2, IL4, IL5, IL6, IL9, IL10, IL12p70, IL13, IL17, IL22, tumor necrosis factor-α (TNFα), and interferon-γ (IFNγ). A cytokine bead immunoassay was used to perform simultaneous measurements. Results The disease involving urinary and respiratory tract constituted 57.5% of all patients. The severity of infection was classified as follows: SIRS patients, n=30; sepsis patients, n=81; and septic shock/severe sepsis patients, n=16. PCT, IL6, and CRP had high area under receiver operation characteristic curve (AUCs) and accuracy, which is as follows: PCT: 0.841, 80.5%; IL6: 0.811, 77.1%; CRP: 0.784, 73.8%, respectively. Severity of sepsis could be discriminated by PCT, IL6, and IL5. Unlike other cytokines, IFNγ had an inverse relation with severity of sepsis. The relationship between cytokine profiles and clinical diagnosis of sepsis was unclear. Conclusions PCT, IL6, and CRP values could assist diagnosis, and PCT, IL6, and IL5 had discriminative properties for determination of severity of sepsis. IFNγ revealed a distinct inverse relationship with severity of sepsis. As there was no relationship between cytokine profiles and sepsis, further studies are required to develop clinical applications.

Cardiac troponin assays: a review of quantitative point-of-care devices and their efficacy in the diagnosis of myocardial infarction

Abstract: Cardiac troponin (cTn) I and T are released from myocardial cells following necrosis, i.e., cell death. An accurate measure of cTn concentrations in a patient ' s blood following ischemia/chest pain can enable provid- ers to determine whether or not a myocardial infarction (MI) has occurred. Point-of-care (POC) devices that meas- ure blood cTn concentrations in under 30 min may help to significantly reduce hospital costs by managing and triaging patients out of the emergency department as quickly as possible. The use of POC devices that measure cTnI and cTnT with a coefficient of variation (CV) ≤ 20% at the 99th percentile upper reference limit (URL) limits both false positive and negative results and provides clinically acceptable findings to assist in appropriate diagnoses. This article reviews nine POC devices that measure cTn in terms of their clinical sensitivity and specificity, analyti- cal imprecision, sample type and preparation, and each assay ' s principle of analysis.

Thyroglobulin measurement by highly sensitive assays: focus on laboratory challenges

Abstract: Differentiated thyroid cancer (DTC) is the most common endocrine cancer and its incidence has increased in recent decades. The initial treatment consists of total thyroidectomy followed by ablation of thyroid remnants by radioiodine in most cases. As thyroid cells are the only source of thyroglobulin (Tg), circulating Tg serves as a biochemical marker of persistent or recurrent disease in the follow-up of DTC. Due to the suboptimal clinical detection rate of older Tg assays endogenous or exogenous thyrotropin (TSH) stimulations are recommended for unmasking occult disease. However, the development of new Tg assays with improved analytical sensitivity and precision at low concentrations now allows detection of very low Tg concentrations, reflecting minimal amounts of thyroid tissue, even without the need for TSH stimulation. Even if the use of these assays still has not found its way in current clinical guidelines, such assays are now increasingly used in clinical practice. As serum Tg measurement is a technically challenging assay and criteria to define a 'highly sensitive' assay may be different, a good knowledge of the technical difficulties and interpretation criteria is of paramount importance for both clinical thyroidologists, laboratory physicians and scientists involved in the care of DTC patients.

Performance criteria for combined uncertainty budget in the implementation of metrological traceability.

Abstract: The measurement uncertainty budget should combine the uncertainty of higher order references, the uncertainty of commercial system calibration, the system imprecision and individual laboratory performance in terms of variability. Here we recommend that no more than one third of the total uncertainty budget, established by appropriate analytical performance specifications, is consumed by the uncertainty of references and approximately 50% of the total budget consumed by the manufacturer's calibration and value transfer protocol. The remaining 50% should be available for the commercial system imprecision (including the batch to batch variation of the reagents) and individual laboratory performance in order to fulfil the uncertainty goal. For commercial systems to work properly, in vitro diagnostics (IVD) manufacturers will need to take more responsibility and ensure the traceability of the combination of platform, reagents, calibrators and control materials for system alignment verification that only as such (as a whole) are certified ("CE marked") by the manufacturer itself in terms of traceability to the selected reference measurement system. Particularly, IVD manufacturers should report the combined (expanded) uncertainty associated with their calibrators when used in conjunction with other components of their analytical system (platform and reagents). This is more than what they are currently providing as traceability and uncertainty information.