The Sequestration Site of Platelets in Idiopathic Thrombocytopenic Purpura: its Correlation with the Results of Splenectomy

S ummary . The clinical usefulness of external scanning data after infusion of 51 Crlabelled platelets into patients with idiopathic thrombocytopenic purpura (ITP) is a matter of controversy. Observations have been made in 575 patients with ITP. Short‐term (6 mth) results of splenectomy were assessed in 206 subjects, and longterm (1‐3 yr) in 153. It appears that the site of sequestration is neither a direct function of the severity of the disease nor of the duration of the disease from the clinical onset. Diffuse sequestration, which cannot be taken as an indication for or against splenectomy, is frequently seen in recent and severe cases. Splenic sequestration is more often observed in young patients (72.5% under 30 yr of age) than in older subjects (36% over 30 yr of age). A good correlation was found between the site of sequestration and the shortand long‐term results of splenectomy: success in more than 90% of cases with splenic sequestration but complete failure in 70% with hepatic sequestration. In any patient with ITP splenectomy should be undertaken only after a careful study of the platelet sequestration site.