Thrombin generation measured by two platforms in patients with a bleeding tendency

Background Mild to moderate bleeding disorders are a diagnostic challenge. Many patients remain undiagnosed despite thorough and repeated laboratory testing. Thrombin generation (TG) is an overall assay measuring the functionality of the hemostatic system and may be a useful tool in diagnosing patients with bleeding tendency. Objectives We examined the added value of TG in patients with mild bleeding tendency with and without diagnosis after classical laboratory testing. Further, we investigated the role of different expressions of results, between-method variation, and reference ranges. Methods TG of patients and controls was measured in parallel by two TG platforms (ST Genesia and calibrated automated thrombogram [CAT]). All TG parameters in patient and control groups were compared by statistical analysis (Mann-Whitney U tests) including visual representation with box-and-whisker plots. Results were expressed as normalized ratios (ST Genesia and CAT) or corrected values (ST Genesia). Reference intervals were calculated to which patient results were compared. We studied lot-to-lot reagent variability for both platforms. Results In 62.7% (ST Genesia) to 69.5% (CAT) of patients undiagnosed with a traditional laboratory work-up, abnormal TG parameters (lag time and endogenous thrombin potential expressed as normalized ratio and/or corrected value) were detected. In the group of previously diagnosed patients, abnormal parameters were found in 58.1% of patients for both TG assays. No relevant lot-to-lot reagent variability was observed. Conclusions Adding TG helps with diagnosing patients with mild bleeding disorder. TG seems a promising tool in diagnosis of bleeding tendency, but further evaluation is necessary before application in diagnostic laboratory testing