Normal subjects, patients with various bleeding disorders, and patients with von Willebrand's disease were studied. All patients with von Willebrand's disease had decreased levels of ristocetin Willebrand factor (range, 0 to 41%) as compared with all other subjects (range, 79 to 202%). Ristocetin induced platelet aggregation of platelet rich plasma was abnormal in all patients with von Willebrand's disease tested, and it was possible to correct this abnormal response by addition of normal platelet poor plasma. Abnormal ristocetin induced platelet aggregation was seen in patients with intrinsic platelet disorders or, on some occasions, in normal patients who had ingested aspirin. Ristocetin induced platelet aggregation is not diagnostic, but it may be useful as a simple screening test for patients with possible von Willebrand's disease. In conjunction with other tests, the assay for ristocetin Willebrand factor will be useful in diagnosis and evaluation of these patients.
ASJC Scopus subject areas
- Pathology and Forensic Medicine