Guidelines on the assessment of bleeding risk prior to surgery or invasive procedures. British Committee for Standards in Haematology.

Unselected coagulation testing is widely practiced in the process of assessing bleeding risk prior to surgery. This may delay surgery inappropriately and cause unnecessary concern in patients who are found to have 'abnormal' tests. In addition it is associated with a significant cost. This systematic review was performed to determine whether patient bleeding history and unselected coagulation testing predict abnormal perioperative bleeding. A literature search of Medline between 1966 and 2005 was performed to identify appropriate studies. Studies that contained enough data to allow the calculation of the predictive value and likelihood ratios of tests for perioperative bleeding were included. Nine observational studies (three prospective) were identified. The positive predictive value (0.03-0.22) and likelihood ratio (0.94-5.1) for coagulation tests indicate that they are poor predictors of bleeding. Patients undergoing surgery should have a bleeding history taken. This should include detail of previous surgery and trauma, a family history, and detail of anti-thrombotic medication. Patients with a negative bleeding history do not require routine coagulation screening prior to surgery.