Institutional performance in application of the FAB classification of acute leukemia. The Southwest Oncology Group experience.

Institutional performance in application of the French-American-British (FAB) classification of acute leukemia in The Southwest Oncology Group is presented, demonstrating a disparity between institutional and expert performance. A significant improvement is shown with an educational effort coupled with experience in use of the classification, and the importance of cytochemistry in the use of the classification is illustrated. A simplification of the classification, merging M1, M2, and M4 as M7, is proposed. This simplification improves institutional performance in use of the classification, while preserving distinctions that appear clinically important.