Prothrombin and partial thromboplastin times as preoperative screening tests
J. M. Eisenberg, J. R. Clarke and S. A. Sussman
Preoperative tests of coagulation function have been suggested to detect
patients who are likely to have abnormal bleeding during and after surgery.
A study was designed to determine the yield of prothrombin time (PT) and
partial thromboplastin time (PTT), both in discovering patients who are at
risk for abnormal bleeding and in inducing changes in patient care or
outcome. Of 750 patients on three surgical services, 611 (81%) patients had
no indication of a bleeding disorder on history or physical examination. Of
the 139 patients who had clinical indications, 25 (18.0%) patients had an
abnormal PT or PTT. Of the 611 patients without clinical indications, 480
patients had the PT or PTT determined, and 13 (2.7%) patients had abnormal
results. One (0.2%) of the 480 patients might have benefited from the test
result (this patient required a second operation to control arterial
bleeding). The prolonged PT or PTT was of no apparent clinical importance
in the remaining 12 patients without indications of bleeding disorders
preoperatively. The low yield of the PT and PTT in detecting unsuspected
bleeding disorders preoperatively was further obscured by the larger number
of apparently false-positive results.
