Misdiagnosis of primary immune thrombocytopenia and frequency of bleeding: lessons from the McMaster ITP Registry

Nonspecific diagnostic criteria and uncertain estimates of severe bleeding events are fundamental gaps in knowledge of primary immune thrombocytopenia (ITP). To address these issues, we created the McMaster ITP Registry. In this report, we describe the methodology of the registry, the process for arriving at the diagnosis, and the frequency of bleeding. Consecutive patients with platelets <150 × 10⁹/L from a tertiary hematology clinic in Canada …