The efficacy of direct, 24-hour culture, and mitotic synchronization methods for cytogenetic analysis of bone marrow in neoplastic hematologic disorders.

Bone marrow aspirates from 90 patients suspected of having a hematologic disorder were processed by using different cytogenetic methods to determine if any procedure was more likely to reveal a chromosomally abnormal clone or produce better-quality metaphases. All specimens were processed by a direct technique and 24-hr culture without mitogens; 50 specimens were also processed by an amethopterin mitotic synchronization method. In each case, the microscope slides were coded by the processing technologist and analyzed by two other experienced cytogenetic technologists. The results were not known to any of the investigators until all 90 specimens were analyzed. With the exception of one specimen, in which a chromosomally abnormal clone was identified only in the direct preparation, no apparent differences were found in the karyotypes among the three methods. Also, the differences in the quality or number of metaphases found among the three methods were not statistically significant; however, 24-hr unstimulated cultures produced more metaphases than the mitotic synchronization procedure. The greatest source of discordance was caused by one test yielding either no metaphases or an uncertain result when the other tests produced a successful study. We suggest that in routine practice at least two different methods should be used, and it may be best if at least one of these methods is a direct technique.