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Updated: May 18, 2026

The Nijmegen Hemostasis Assay: Simultaneous Fluorogenic Measurement of Thrombin and Plasmin Generation in a Single Well
Published on: February 27, 2026
Laboratory investigations for bleeding disorders
Catherine P M Hayward1, Karen A Moffat, Yang Liu
1Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. haywrdc@mcmaster.ca
Bleeding disorder panels often include the prothrombin time (PT)/international normalized ratio (INR), activated partial thromboplastin time (APTT), fibrinogen level, and thrombin time (TT). We explored the detection of abnormalities from bleeding disorders by these tests among subjects referred for bleeding disorder assessments, using data from a bleeding disorder study to determine sensitivities and specificities. Among subjects referred to hematologists for bleeding disorder assessment, coagulation defects were uncommon and the APTT and TT detected many nonsignificant abnormalities. While all test and panel specificities were acceptable (88 to 100%), coagulation screening tests were less sensitive to clinically significant abnormalities (1.0 to 2.1%) than von Willebrand disease (VWD) screens (6.7%), and light transmission platelet aggregometry (LTA) (26%). Accordingly, panels comprising PT/INR, APTT, fibrinogen, and TT had lower sensitivity to bleeding disorders (3.7%) than panels expanded to include VWD screens (8.5%), or VWD screens and LTA (30%). These findings have important implications for bleeding disorder diagnosis.
Bleeding disorder panels often include the prothrombin time (PT)/international normalized ratio (INR), activated partial thromboplastin time (APTT), fibrinogen level, and thrombin time (TT). We explored the detection of abnormalities from bleeding disorders by these tests among subjects referred for bleeding disorder assessments, using data from a bleeding disorder study to determine sensitivities and specificities. Among subjects referred to hematologists for bleeding disorder assessment, coagulation defects were uncommon and the APTT and TT detected many nonsignificant abnormalities. While all test and panel specificities were acceptable (88 to 100%), coagulation screening tests were less sensitive to clinically significant abnormalities (1.0 to 2.1%) than von Willebrand disease (VWD) screens (6.7%), and light transmission platelet aggregometry (LTA) (26%). Accordingly, panels comprising PT/INR, APTT, fibrinogen, and TT had lower sensitivity to bleeding disorders (3.7%) than panels expanded to include VWD screens (8.5%), or VWD screens and LTA (30%). These findings have important implications for bleeding disorder diagnosis.
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