Reassessment of a cytochemical test for differential diagnosis of leukemic reticuloendotheliosis.

Reports of negative tartrate-resistant acid phosphatase reactions in a few cases of leukemic reticuloendotheliosis prompted the authors to re-evaluate the diagnostic specificity of this test. As a result, they modified the test by (1) incorporating a dual-control system for excluding a false-negative test due to technical errors, and (2) instituting an objective grading system for assuring consistent interpretation of the test on blood smears. When these modifications were applied to materials of patients suspected to have leukemic reticuloendotheliosis, there was an excellent, although not specific, correlation between the positive test and the diagnosis of leukemic reticuloendotheliosis. Tartrate-resistant acid phosphatase reactions were positive, intermediate, and negative for 76, 21, and 3% of 29 patients who had leukemic reticuloendotheliosis, whereas the figures were 3, 32, and 65%, respectively, for 37 patients who had chronic lymphocytic leukemia and other hematologic disorders.