The value of measuring platelet "adhesiveness" in the diagnosis of bleeding diseases.

Platelet retention was decreased in many hemorrhagic states, including von Willebrand’s disease, qualitative platelet diseases, and a variety of other conditions. It also was abnormal in two of four patients with acquired inhibitors of factor VIII. With the exception of von Willebrand’s disease, these conditions are diagnosed on the basis of tests other than platelet retention. Although the result of a test of platelet retention is of interest as part of the assessment of platelet function, it is crucial only in the diagnosis of von Willebrand’s disease. Furthermore, an abnormality in the test should lead one to suspect von Willebrand’s disease in patients in whom the diagnosis has been obscured by an increase in the factor VIII level as a result of birth control medicaments, pregnancy, or transfusions.