Utilization of flow cytometry for diagnosis of hematologic malignancies in Thailand: increasing trends and diagnostic yields in 7,982 samples.

BACKGROUND Diagnosis of hematologic malignancies requires a multidisciplinary approach. Flow cytometry (FCM) has become an essential tool for immunophenotypic studies of malignant hematopoietic cells. OBJECTIVE To evaluate the utilization trend of FCM and its diagnostic yields for hematologic malignancy at a major teaching hospital in Thailand. MATERIAL AND METHOD FCM results of bone marrow (BM) and peripheral blood (PB) specimens during 2000-2013 were analyzed and compared to clinical diagnosis. RESULTS Overall, 7,982 specimens were submitted for diagnostic FCM including 6,561 BM and 1,421 PB. The number of specimens analyzedwas 121, 142, 164, 299, 491, 431, 690, 611, 719, 744, 725, 863, 955 and 1,027, respectively, from 2000 to 2013. The most common clinical diagnoses requested for FCM were acute leukemia (5,911 cases, 74%) followed by lymphoma (1,419 cases, 17.8%), and chronic lymphocytic leukemia (CLL) (634 cases, 7.94%). The highest diagnostic yield of FCM was found in acute leukemia cases (69.71%) followed by CLL (35.33%). Only 15.43% of clinically suspected lymphoma cases were positive by FCM. Overutilization of PB (35.6% of cases) instead of BM for lymphoma staging significantly contributed to low diagnostic yields of lymphoma by FCM as circulating tumor cells may not be present in such cases. CONCLUSION FCM has an increasing role in the diagnosis of hematologic malignancies in Thai patients over the past 14 years with the highest diagnostic yield in acute leukemia. Appropriate specimen types and study indications are required in order to reduce futility of costly diagnostic tests and improve diagnostic yields.