Towards standardization of thrombin generation assays: Inventory of thrombin generation methods based on results of an International Society of Thrombosis and Haemostasis Scientific Standardization Committee survey.

BACKGROUND: Thrombin generation (TG) is a better determinant of the overall function of the hemostatic system than the routinely used clotting time-based assays. Nowadays, TG is widely used in hemostasis research teams, for both clinical and basic research. However, there is significant variability between laboratories regarding preanalytics, reagents, TG protocol, analysis interpretation, and normalization. OBJECTIVES: To document the extent of variation in the methodology of TG, we aim to collect all the methods that are being used to measure TG in a survey. METHODS: We organized a questionnaire through the Standardization committee for Lupus Anticoagulant/Antiphospholipid Antibodies of the International Society of Thrombosis and Haemostasis Scientific Standardization committee. The questionnaire consisted of 51 questions regarding the different aspects of TG: type of users, methods, sample type, analysis, and interpretation of results, normalization, and quality control. RESULTS: Of the 240 surveys that were started, 108 were completed (45%). However, not all questions were in scope for all laboratories. One-half of the laboratories were research laboratories and half diagnostic laboratories. The most used TG assay was the calibrated automated thrombinography-based assay (56%). There was a divergence regarding several aspects of the TG assay: type of needle for blood collection, blood tubes, centrifugation, sample storage and thawing, reagents, sample dilution, calibration, reference ranges, data normalization, and so on. CONCLUSIONS: There is an important variation in the methods used for measuring TG. A standardized protocol and data normalization should lead to a better reproducibility and for comparing data from different laboratories.