A prospective cohort study to identify clinical diagnostic and prognostic markers of primary immune thrombocytopenia in dogs.

Background: Primary immune thrombocytopenia (pITP) in dogs presents a diagnostic challenge, and clinical markers of severity are lacking.

Objectives: Identify clinicopathologic features that differentiate pITP from secondary ITP (sITP) and markers related to bleeding severity, transfusion, and survival of dogs with pITP.

Animals: Ninety-eight thrombocytopenic dogs (58 pITP and 40 sITP).