The activated plasma recalcification time. A Measurement encompassing the activated partial thromboplastin time and platelet function, with improved detection of bleeders.

A study of 300 patients is presented to demonstrate the effectiveness of the activated plasma recalcification time (APRT) as a measure of the intrinsic pathway and platelet function in the detection of bleeders. The activated partial thromboplastin time (APTT) and platelet count were determined in all patients having both normal and abnormal APRT's and the results correlated with overt bleeding tendencies. Abnormality of the APTT is closely paralleled by abnormality of the APRT, independent of the platelet count. When the APTT is normal, an abnormal APRT will characterize clinical bleeders with greater frequency than will the platelet count. The value of the APRT is greatest when done in concert with other standard coagulation measurements, as it both reinforces and expands their diagnostic capability.