Quality in coagulation and haemostasis testing

The essential elements of a quality program, specifically internal quality control (IQC) and external quality assurance (EQA), should be applied to each laboratory assay performed in order to ensure test result accuracy and precision. The coagulation laboratory plays an important role in the diagnosis and treatment of individuals with bleeding or clotting (i.e., thrombotic) disorders. Test methodologies used to assess common disorders or diseases of haemostasis are reviewed as well as the clinical relevance of each assay. The preanalytical phase of testing offers the greatest opportunity for introducing result error in the haemostasis laboratory and it is therefore imperative that samples are properly collected, transported and stored. Samples for haemostasis testing should be collected in 3.2% sodium citrate at a 9:1 blood to anticoagulant ratio and maintained at room temperature until processed. Some test processes such as platelet function testing have special processing and testing requirements. For plasma-based tests, centrifugation to obtain platelet poor plasma and testing should ideally be completed within 4 hours or the plasma frozen. IQC must be performed with each assay, at appropriate levels of the analyte and at appropriate time intervals as a means for assessing ongoing assay performance. EQA, a peer group assessment process that is supplementary to IQC, offers in addition the opportunity for evaluation of long-term performance of laboratories, including comparisons with like and unlike methodologies, and often serves as an educational resource. Participation in an EQA program is often a requirement of laboratory accreditation and there are a multitude of EQA organizations that offer programs specific to haemostasis testing with international programs providing assessment of the more specialized haemostasis assays. These programs provide invaluable information on assay specific diagnostic error rate, assay precision, accuracy, sensitivity and assessment of overall assay performance. The incorporation of IQC and EQA into a laboratory program can not only assist in the assurance that testing is reliable and accurate but also improve the quality of the testing

Re-engineering laboratory diagnostics for preventing preanalytical errors

Re-engineering laboratory diagnostics for preventing preanalytical error

Critical pre-examination variables in the hemostasis laboratory and their quality indicators

The total testing process comprises a number of phases of laboratory testing, which can be broadly considered as comprising pre-examination, examination and post-examination activities. Although each phase is crucial to providing accurate and meaningful laboratory results, the pre-examination phase of testing is where most laboratory errors currently occur, and thus requires special attention. The activities in this phase include sample collection, handling, transportation, processing and storage, which are frequently outside the control of the laboratory performing the tests. Samples for hemostasis testing are particularly vulnerable to pre-analytical variables, which may ultimately lead to inappropriate test results. We outline here several strategies to mitigate potential problems in the pre-examination phase. We also recommend the implementation of several processes to reduce errors

Factor V Leiden-independent activated protein C resistance:Communication from the plasma coagulation inhibitors subcommittee of the International Society on Thrombosis and Haemostasis Scientific and Standardisation Committee

Activated protein C resistance (APC-R) due to the single-nucleotide polymorphism factor V Leiden (FVL) is the most common cause of hereditary thrombophilia. It is found predominantly in Caucasians and is uncommon or absent in other populations. Although FVL is responsible for &gt;90% of cases of hereditary APC-R, a number of other F5 variants that also confer various degrees of APC-R and thrombotic risk have been described. Acquired APC-R due to increased levels of coagulation factors, reduced levels of inhibitors, or the presence of autoantibodies occurs in a variety of conditions and is an independent risk factor for thrombosis. It is common for thrombophilia screening protocols to restrict assessment for APC-R to demonstrating the presence or absence of FVL. The aim of this Scientific and Standardisation Committee communication is to detail the causes of FVL-independent APC-R to widen the diagnostic net, particularly in situations in which in vitro APC-R is encountered in the absence of FVL. Predilution clotting assays are not FVL specific and are used to detect clinically significant F5 variants conferring APC-R, whereas different forms of acquired APC-R are preferentially detected using the classical activated partial thromboplastin time-based APC-R assay without predilution and/or endogenous thrombin potential APC-R assays. Resource-specific recommendations are given to guide the detection of FVL-independent APC-R.</p

Mixing of thawed coagulation samples prior to testing: Is any technique better than another?

Thus study was aimed to investigate whether the mixing technique could influence the results of routine and specialized clotting tests on post-thawed specimens