- In some medical centers, the routine pre-operative evaluation of healthy children undergoing elective tonsillectomy and/or adenoidectomy (T and A) includes coagulation screening tests (PT, prothrombin Time; PTT, partial thromboplastin time; and INR, international normalized ratio). In this retrospective study, we determined whether there is a positive correlation between prolonged PT/PTT/INR tests in healthy children, with no prior medical history of coagulation problems, and bleeding during surgery and/or bleeding in the month following surgery. We reviewed the records of 416 elective T and A surgeries performed at the Soroka University Medical Center in Beer-Sheva, Israel, over the course of 1999. One hundred and twenty-one (29.1%) patients had preoperative prolonged PT values but only four (3.3%) of these patients experienced light bleeding during surgery. Seven (5.8%) of the 121 patients with prolonged PT tests experienced bleeding episodes during the 1st month subsequent to the surgery. Of the 65 (15.6%) patients who had prolonged pre-operative INR values, only three (4.6%) experienced light bleeding during surgery. Two (3.1%) patients with prolonged INR values experienced light bleeding during the 1st month subsequent to surgery. Sixty-one (14.7%) patients had prolonged first preoperative PTT values, only five of whom (8.2%) experienced light bleeding during surgery. Two (3.3%) of the 61 with prolonged PTT values experienced light bleeding during the 1st month subsequent to surgery. We therefore concluded that pre-operative coagulation screening tests provide low sensitivity and low bleeding predictive value. As such, routine coagulation tests before T &A are not indicated unless a medical history of bleeding tendency is suspected.