Sir.—I have read with interest Halperin and Doyle's article1 and Corrigan's editorial2 about bone marrow examination in idiopathic thrombocytopenic purpura (ITP). I would like to add a few points.
The authors do not mention that bone marrow examination also excludes megaloblastic anemia, which rarely presents with thrombocytopenia.
Corrigan2 states that "there is no laboratory test that is diagnostic of ITP in children." I believe that antiplatelet antibody determination by the modified Handin and Stossel method3 would serve this purpose. So far, antibodies have been determined in 177 acute cases (90 in the thrombocytopenic phase, 87 in remission, and 54 cases in both conditions) and in 55 chronic cases (35 in the thrombocytopenic period, 20 in remission, and eight cases in both conditions) of ITP. It was also studied in 126 controls (67 patients without hematologic disorders and 59 thrombocytopenic controls: 28 patients with leukemia, ten with aplastic anemia, ten with