Reticulated platelets in the evaluation of thrombopoietic disorders.

The laboratory diagnosis of immune platelet destruction has relied predominantly on the presence or absence of megakaryocytes in bone marrow. Recently, examination of peripheral blood platelets for high RNA content (reticulated platelets) or for elevated levels of platelet-associated IgG have been suggested as less invasive diagnostic tests. We used thiazole orange fluorescence labeling to determine the percentage of circulating reticulated platelets and two antibodies with different specificities directed against human IgG to measure platelet-associated IgG by flow cytometry in 59 patients with either immune thrombocytopenic purpura (n = 23) or chemotherapy-induced thrombocytopenia (n = 36).

Reevaluation of the periodic acid-Schiff stain in acute leukemia with immunophenotypic analyses.

To determine the sensitivity and specificity of the periodic acid-Schiff (PAS) stain in the diagnosis of acute leukemia in light of the finer characterization of this disorder now available through immunophenotyping, we examined the blasts from 51 patients with newly diagnosed acute leukemia by morphological, cytochemical, and immunophenotypic analyses. The 51 patients represented every new case of acute leukemia subjected to cytochemical stains and flow cytometry between July 1987 and February 1989. By cell-surface marker analysis, 29 exhibited lymphocytic lineage, while 21 were myelocytic.