OBJECTIVETo optimize pre-coated multiple-probe fluorescence in situ hybridization (FISH) to improve its efficiency in cytogenetic diagnosis of acute leukemia.

METHODSThe original multiple-probe FISH techniques were optimized by adjusting the cell density and adding a process of protease digestion. Cytogenetic anomalies were detected in 141 patients with acute lymphocytic leukemia (ALL) or acute myeloid leukemia/ myelodysplastic syndromes (AML/MDS) using the modified technique, and 35 of the patients were also examined using the original technique. The successful detection rate and positive site detection rate were compared between the modified and original techniques.

RESULTSModification of the pre-coated multiple-probe FISH technique resulted in an significant increase of the successful detection rate (from 85.3% to 100%) and the positive site detection rate (from 5.1% to 8.6%) in ALL patients; in AML/MDS patients, the successful detection rate was significantly improved from 67.4% to 99.8% and the positive site detection rate from 3.5% to 6.0% (P<0.01).

CONCLUSIONThe modified pre-coated multiple-probe FISH technique can significantly increase the diagnostic efficiency of cytogenetic abnormalities in leukemic patients.