Fibrinogen/fibrin degradation products in serum of patients with idiopathic thrombocytopenic purpura: elevated levels during severe thrombocytopenic phase of the disease.

Sera from 23 patients with idiopathic thrombocytopenic purpura (ITP), 14 patients with aplastic anemia with severe thrombocytopenia and healthy control subjects were tested for the presence of fibrinogen/fibrin degradation products (FDP), using the tanned red cell hemagglutination inhibition immunoaassay. The concentrations of circulating FDP of ITP patients (mean 12.01 mug/ml) were significantly higher than those of the patients with aplastic anemia (mean 4.01 mug/ml, p less than 0.05) or normal controls (mean 3.10 mug/ml, p less than 0.001). The patients with untreated ITP with very low platelet counts had higher levels of FDP than those of the treated group (p less than 0.01). Serum FDP and a battery of other coagulation-fibrinolysis tests were serially carried out over a period of 10 weeks in two patients with ITP. The initially high FDP promptly decreased as circulating platelets increased in response to steroid in both patients, while plasma fibrinogen, euglobulin lysis time, prothrombin time and partial thromboplastin time remained essentially normal during the course of observation. The exact source of the increased serum FDP in ITP was not established, but a few possible mechanisms responsible for this abnormality were discussed.