[Temperature-dependent spontaneous platelet aggregation in polycythemia vera and primary thrombocythemia: a diagnostic criterion].

In twenty patients suffering from myeloproliferative syndromes (nine with polycythaemia vera, 11 with primary thrombocythaemia) platelet aggregation was tested following incubation of blood samples at 4 degrees C, room temperature, 30 degrees C and 37 degrees C. A spontaneous platelet aggregation following incubation at room temperature took place in 65% of patients with primary thrombocythaemia. At the two higher temperatures, positive results were seen in 72% and 92% of cases, respectively. Seven of nine patients (78%) showed a pathological spontaneous platelet aggregation at room temperature. Pathological spontaneous platelet aggregation at 30 degrees C occurred in eight of nine (89%) cases. The spontaneous platelet aggregation test is a simple method to diagnose primary thrombocythaemia and asymptomatic polycythaemia vera, the sensitivity of which increases considerably following incubation of blood samples at two and three different temperatures.