INTRODUCTION:We aimed at evaluating the performance of a new prothrombin time (PT) reagent (STA-NeoPTimal) with two other PT reagents (STA-Neoplastine R and STA-Neoplastine CI Plus) and the reference PT reagent used in our laboratory (ReadiPlasTin). METHODS:Evaluation consisted in intra- and interassay precision assessment, determination of sensitivity to unfractionated heparin (UFH) or enoxaparin in spiked samples and to direct oral anticoagulants (DOACs) in patients (n = 43). Method comparison of the 4 PT reagents, factor II, V, VII and X assays was tested on normal (n = 20) and abnormal samples: VKA (n = 47), preoperative (n = 23), liver failure (n = 12) and burned patients (n = 37). RESULTS:Analytical performance met manufacturers' criteria for all reagents. All PT reagents gave correlation coefficients >0.8 and even >0.9 in many situations. In some VKA samples, differences ≥ 0.5 INR units were found in samples within and above therapeutic ranges. For burned patients, PT correlations were good but with some minimal bias (<5.0%) while factor assays gave very consistent results (R > .8 and mainly >0.9). As expected, poor responsiveness of the PT to DOAC concentrations was observed with all four assays. CONCLUSION:The STA-NeoPTimal showed comparable performance to ReadiPlasTin, making it suitable for VKA control, detection of factors II, V, VII, X deficiency and assessment of liver disease coagulopathy. However, for patients receiving VKA, some significant differences were observed. We confirmed the inability of the PT assay to detect residual DOAC concentrations. Finally, burned patients results showed that recombinant thromboplastins were less sensitive to factor deficiencies in comparison to extraction thromboplastins.

Background Thrombin generation testing has been used to provide information on the coagulation phenotype of patients. The most used technique is the calibrated automated thrombogram (CAT) but it suffers from a lack of standardization, preventing its implementation in routine. The ST Genesia is a new analyzer designed to assess thrombin generation based on the same principle as the CAT. Unlike the CAT system, the ST Genesia is a benchtop, fully automated analyzer, able to perform the analyses individually and not by batch, with strict control of variables such as temperature and volumes, ensuring, theoretically, maximal reproducibility. Objectives This study aimed at assessing the performance of the STG-DrugScreen application on the ST Genesia analyzer. We also aimed at exploring stability of plasma samples after freezing and defining a reference normal range. Results Results demonstrated the excellent interexperiment precision of the ST Genesia and confirmed that the use of a reference plasma helps reducing the inter-experiments variability. Stability revealed that plasma samples are stable for at least 11 months at -70 degrees C or lower, except for those containing low molecular weight heparins which have to be tested within 6 months. Freezing had no effect on the majority of thrombin generation parameters except on time to peak. Conclusions Our results suggest an easy implementation of thrombin generation with the use of ST Genesia in the routine laboratory. This will facilitate the design of multicentric studies and enable the establishment of reliable and evidence-based thresholds, which may improve the management of patients treated with anticoagulants.

INTRODUCTION:Betrixaban is a novel direct oral factor Xa inhibitor approved by the Food and Drug Administration for prophylaxis of venous thromboembolism in adult patients hospitalized for an acute illness at risk for thromboembolic complications. Assessment of the anti-coagulant effect of betrixaban may be useful in some situations. Also, clinicians need to know how routine coagulation assays are influenced.OBJECTIVE:The aim of this study is to determine which coagulation assay(s) should be used to assess the impact of betrixaban on haemostasis and provide laboratory guidance for their interpretation.MATERIALS AND METHODS:Betrixaban was spiked at final concentrations ranging from 0 to 250 ng/mL in platelet-poor plasma. Different reagents from several manufacturers were tested and the impact of betrixaban on pro-thrombin time (PT), activated partial thromboplastin time (aPTT), dilute Russel viper venom time (dRVV-T), chromogenic anti-Xa assays, thrombin generation assay (TGA), and a large panel of haemostasis diagnostic tests has been assessed.RESULTS:A concentration-dependent prolongation of aPTT, PT and dRVV-T is observed. The sensitivity mainly depends on the reagent. Chromogenic anti-Xa assays show high sensitivity depending on the reagent and/or the methodology. These assays applicable for other direct factor Xa inhibitors have to be adapted to obtain a relevant range of measurement. TGA may also be attractive to assess the anti-coagulant activity of betrixaban.CONCLUSION:Adapted chromogenic anti-Xa assays are the most appropriate assays to estimate the concentration of betrixaban. Betrixaban significantly affects several haemostasis diagnostic tests and this needs to be taken into consideration when requesting and interpreting such tests.