Role of FAB classification of acute leukemias in era of immunophenotyping.

French-American-British classification for leukemias had been widely accepted due to its objectiveness and good reproducibility. WHO classification of leukemias was formulated in 1997 with a purpose of further enhancing the objectivity. However, the requirement of cytogenetics and immunophenotyping makes it difficult for many countries like India to put WHO classification in routine use. This study was carried to know the effectiveness of FAB classification in an era of technical advancement. A retrospective analysis of all acute leukemias over a period of 2 years was done. Out of total of 469 cases of acute leukemias, 193 were diagnosed as Acute Lymphoblastic Leukemia (ALL), 200 as Acute Myeloid Leukemia (AML), and 76 cases diagnosed as Acute Leukemia, cytochemically undifferentiated. Hence, only 16% of all leukemias remained unclassifiable. Subclassification of AML cases revealed a much higher percentage of AML-M3, as compared to western literature. In conclusion, FAB classification, based on morphology and simple cytochemical stains, remains effective enough, although cytogenetics and immunophenotyping can add to diagnostic accuracy in some cases.