Abstract
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.
Keywords
bleeding disorders - laboratory testing - factor deficiencies - fibrinogen