Publications by authors named "Piet Meijer"
External quality assessment (EQA) enhances patient safety through the evaluation of the quality of laboratory-based and point of care testing. Regulatory agencies and accreditation organizations utilize the results and the laboratory's response to them as part of assessing the laboratory's fitness to practice. In addition, where EQA samples are commutable and the assigned value has been determined using reference measurement procedures (RMPs), EQA data contributes to the verification of metrological traceability of assays as part of the post-market surveillance of diagnostic (IVD) medical devices (IVD-MDs).
View Article and Find Full Text PDFProviders of external quality assessment (EQA) programs evaluate data or information obtained and reported by participant laboratories using their routine procedures to examine properties or measurands in samples provided for this purpose. EQA samples must offer participants an equal chance to obtain accurate results, while being designed to provide results in clinically relevant ranges. It is the responsibility of the EQA provider to meet the necessary requirements for homogeneity, stability and some other properties of the EQA items in order to offer participants a fair, reliable and technically interesting EQA experience.
View Article and Find Full Text PDFIt is important that a clinical laboratory has implemented appropriate procedures for quality control, which includes both internal quality control (IQC) and external quality assessment (EQA) with the common goal to detect systematic errors and random errors. It is the case for both the Hemohub® Bayesian tools for IQC results interpretation and the ECAT EQA optimised bivariate z-scores analysis. On a concrete case study, we demonstrate both the higher sensitivity and specificity of optimised bivariate z-scores analysis than the univariate approach.
View Article and Find Full Text PDFD-dimer assessment has several established roles in venous thromboembolism (VTE) and disseminated intravascular coagulation diagnosis, and recently the risk stratification of coronavirus disease 2019 (COVID-19). D-dimer assays are neither standardized nor harmonized, use varying methodologies, and use different reporting units, all resulting in a lack of interchangeability and generalizability of assays. Using large multiyear datasets from an international laboratory quality assurance program, we assessed (1) common D-dimer assays in use worldwide, (2) differences in analytical performance between different methods, and (3) interlaboratory variability between positive samples.
View Article and Find Full Text PDFComparison of Thrombophilia Assay Results for the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee Plasma Standard from Different External Quality Assessment Providers-for the External Quality Assurance in Thrombosis and Haemostasis Group.
Semin Thromb Hemost
August 2024
External quality assessment (EQA) is used to evaluate laboratory performance in tests of hemostasis; however, some esoteric tests are performed by too few centers in any one EQA program to allow valid statistical assessment. To explore the feasibility of pooling data from several EQA providers, an exercise was carried out by the External Quality Assurance in Thrombosis and Haemostasis group, using the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee (SSC) plasma standard for thrombophilia screening assays. Six EQA providers took part in this exercise, distributing the SSC plasma standard as a "blinded" sample to participants for thrombophilia tests between November 2020 and December 2021.
View Article and Find Full Text PDFMetrology in clinical chemistry aims to ensure the equivalence of measurement results from different in-vitro diagnostic measurement devices (IVD MD) for use in healthcare. The metrological traceability of measurement results to higher-order references is the cornerstone to achieving equivalent results. However, other fundamentals are also needed, including the commutability of reference materials and external quality assessment (EQA) materials for monitoring the equivalence of measurement results at the end-user level.
View Article and Find Full Text PDFObjectives: The aim of this study is to develop a practical method for bivariate z-score analysis which can be applied to the survey of an external quality assessment programme.
Methods: To develop the bivariate z-score analysis, the results of four surveys of the international D-Dimer external quality assessment programme of 2022 of the ECAT Foundation were used. The proposed methodology starts by identifying the bivariate outliers, using a Supervised Sequential Hotelling T control chart.
D-dimer diagnostics: can I use any D-dimer assay? Bridging the knowledge-to-action gap.
Res Pract Thromb Haemost
January 2024
A State of the Art lecture titled "D-dimer Diagnostics: Can I use any D-dimer assay? Bridging the Knowledge-to-Action gap" was presented at the International Society on Thrombosis and Haemostasis Congress in 2023, included in the session on the clinical impact of variability in commonly used coagulation assays. Here, we review the role of D-dimer, primarily in the outpatient diagnosis of patients with venous thromboembolism (VTE) when combined with clinical decision rules. We focus on the recent large management trials that have studied adjustments of VTE exclusion thresholds for D-dimer based on either prior clinical probability of VTE or patient age, and the resultant benefit of reduced imaging for VTE and improved diagnostic efficiency.
View Article and Find Full Text PDFDefining a metrologically traceable and sustainable calibration hierarchy of international normalized ratio for monitoring of vitamin K antagonist treatment in accordance with International Organization for Standardization (ISO) 17511:2020 standard: communication from the International Federation of Clinical Chemistry and Laboratory Medicine-SSC/ISTH working group on prothrombin time/international normalized ratio standardization.
J Thromb Haemost
April 2024
Calibration of prothrombin time (PT) in terms of international normalized ratio (INR) has been outlined in "Guidelines for thromboplastins and plasmas used to control oral anticoagulant therapy" (World Health Organization, 2013). The international standard ISO 17511:2020 presents requirements for manufacturers of in vitro diagnostic (IVD) medical devices (MDs) for documenting the calibration hierarchy for a measured quantity in human samples using a specified IVD MD. The objective of this article is to define an unequivocal, metrologically traceable calibration hierarchy for the INR measured in plasma as well as in whole blood samples.
View Article and Find Full Text PDFThis guidance document has been prepared on behalf of the International Council for Standardisation in Hematology. The aim of the document is to provide guidance and recommendations on the measurement of factor VIII (FVIII) and factor IX (FIX) inhibitors. After an introduction on the clinical background and relevance of factor VIII and factor IX inhibitor testing, the following aspects of laboratory testing are included: screening for inhibitors, assay principle, sample requirements, testing requirements and interpretation, quality assurance, interferences and recent developments.
View Article and Find Full Text PDFObjectives: The diagnosis and monitoring of bleeding and thrombotic disorders depend on correct haemostatic measurements. The availability of high-quality biological variation (BV) data is important in this context. Many studies have reported BV data for these measurands, but results are varied.
View Article and Find Full Text PDFBackground: Reduced or dysfunctional von Willebrand factor (VWF) may lead to von Willebrand disease (VWD), which is a common inherited bleeding disorder. VWD is classified into three major types: type 1 is a partial quantitative deficiency of VWF, type 3 is a complete quantitative deficiency of VWF, and type 2 consists of qualitative abnormalities of VWF. To arrive at a correct VWD diagnosis, multiple tests and a correct interpretation of these tests are needed.
View Article and Find Full Text PDFAccurate diagnosis of von Willebrand disease (VWD) depends on the quality, precision, and variability of the laboratory assays. The North American Specialized Coagulation Laboratory Association (NASCOLA) is a provider of external quality assessment (EQA) for approximately 60 specialized coagulation laboratories in North America. In this report, NASCOLA EQA data from 2010 to 2021 are reviewed for trends in methodology and precision among various assays.
View Article and Find Full Text PDFOn May 26th 2017 the European Parliament and the Council of The European Union adopted the new regulation on in vitro diagnostic medical devices (IVDR)-Regulation EU 2017/746-planned to be applied from May 26th 2022 in substitution to the previous IVD directives (IVDD 98/79 EC). After several health and legal causes due to medical device malfunctions, the European Union (EU) extensively reviewed the previous regulatory, which had remained unchanged since 1998. Aim of the work is to analyse the effects of the new IVDR on the field of haemostasis and thrombosis testing with particular attention to specific clinical conditions.
View Article and Find Full Text PDFBackground: Providing evidence-based interpretative comments (IC) is an integral task of clinical laboratory professionals. It may be of special relevance for coagulation testing, where pathological first-line tests could trigger more specialized tests. Our aim was to evaluate the quality of ICs provided to the physician in two samples with activated partial thromboplastin time (APTT) prolongation.
View Article and Find Full Text PDFBackground: Reduced or dysfunctional von Willebrand factor (VWF) may lead to von Willebrand disease (VWD), which is a common inherited bleeding disorder. VWD is classified into three major types: type 1 is a partial quantitative deficiency of VWF, type 3 is a complete quantitative deficiency of VWF, and type 2 consists of qualitative abnormalities of VWF. To arrive at a correct VWD diagnosis, multiple tests and a correct interpretation of these tests are needed.
View Article and Find Full Text PDFBackground: Unexpected prolongation of first-line coagulation tests, including activated partial thromboplastin time (APTT), should trigger further work-up by performing mixing tests to elucidate the underlying cause, direct further specific testing and clarify their possible clinical impact. The aim of our study was to assess whether methodological diversity has any impact on the APTT mixing test results and their interpretation.
Material And Methods: Two lyophilized plasma samples (case 1: heparin contamination [0.
Background: Vaccine-induced immune thrombocytopenia and thrombosis (VITT) following the administration of the AstraZeneca (AZ) ChAdOx1 nCOV-19 vaccine is a well recognized clinical phenomenon. The associated clinical and laboratory features have included thrombosis at unusual sites, thrombocytopenia, raised D-dimer levels and positivity for immunoglobulin G (IgG) anti-platelet factor 4 (PF4) antibodies.
Objectives: A collaborative external quality assessment (EQA) exercise was carried out by distributing five lyophilized samples from subjects with VITT and one from a healthy subject to 500 centers performing heparin-induced thrombocytopenia (HIT) testing.
Introduction: The high incidence of thrombotic events in patients with COVID-19 affects health care worldwide and results in an increased workload in haemostasis laboratories due to more frequent testing of D-dimer, haemostatic parameters and anti-Xa tests. However, the impact of this increase in assay requests on the quality of performance in haemostasis laboratories remains unclear. In this study, the impact of the COVID-19 pandemic on the quality of performance and management of haemostasis laboratories was evaluated.
View Article and Find Full Text PDFBackground: Laboratory diagnosis of von Willebrand Disease (VWD) is complex. Reliance on laboratory testing can be problematic as different VWD screening panels, assays and methodologies can produce analytic variability in test results.
Objectives: To compare the degree of imprecision among the VWD assays and within the platelet binding activity (PBA) assays, to determine the consensus among the VWD assays for correct classification of sample results, and to determine consensus among laboratories' von Willebrand factor (VWF) multimer interpretations and final interpretations of the VWD panels.
Objectives Chromogenic anti-activated factor X (FXa) assays are currently the "gold standard" for monitoring indirect anticoagulants. However, anti-FXa has been shown to vary according to the choice of reagents. In the present study, the performance of anti-FXa measurement was evaluated in order to gain more insight into the clinical applications.
View Article and Find Full Text PDFBackground: Patients with hemophilia B are increasingly treated with extended half-life (EHL) factor IX (FIX) concentrates. For the laboratory, introduction of these EHL concentrates presents a major challenge. To understand the variation in FIX activity levels, all available diagnostic assays need to be directly compared.
View Article and Find Full Text PDFHereditary deficiency of antithrombin, a natural anticoagulant, causes a thrombophilia with a high risk for venous thromboembolism. Guidance for laboratory testing to diagnose antithrombin deficiency include the use of an activity assay for initial testing, performing an antigen test and activity-to-antigen ratio when the activity level is low, using pediatric reference ranges until the age of 6 months, excluding acquired causes of low antithrombin (e.g.
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