To compare the effects of direct fluorescence in situ hybridization (D-FISH) detection without sorting and CD138 immunomagnetic bead sorting technology combined with FISH (MACS-FISH) on cytogenetic analysis of patients with multiple myeloma (MM).FISH test results of 229 patients with initial MM were retrospectively analyzed. The patients were divided into two groups, 140 patients were tested with D-FISH and 89 patients with MACS-FISH. The combination probe was designed as P53, D13S319, RB1, 1q21, and IgH. Cytogenetic detection results were compared between the two groups.The total detection rate of cytogenetic abnormalities in D-FISH group was 52.9%, and that in MACS-FISH group was 79.8%. There was a significant difference in the cytogenetic abnormality rate between the two groups (P=0.020). The abnormal genes with the highest detection rate in the two groups were 1q21 and IgH, respectively, while the lowest was P53. There was no significant difference in the percentage of P53 positive cells (positive rate) between the two groups, while D13S319, RB1, 1q21, and IgH showed significant difference in positive cell rate (P=0.0002, P<0.0001, P=0.0033, P=0.0032). There was no significant correlation between the proportion of plasma cells (PC) detected by bone marrow morphology and cytogenetic abnormality rate in the D-FISH group, while there was a correlation between the proportion of PC detected by flow cytometry and cytogenetic abnormality rate (r=0.364). The PC proportion detected by bone marrow morphology and flow cytometry in the MACS-FISH group had no correlation with the cytogenetic abnormality rate and positive cell rate of the 5 genes mentioned above. Additionally, the PC proportion detected by bone marrow morphology and flow cytometry showed significant difference (P<0.0001).CD138 immunomagnetic bead sorting combined with FISH technology can significantly improve the abnormality detection rate of MM cytogenetics.CD138免疫磁珠分选结合荧光原位杂交技术在多发性骨髓瘤中的应用.比较未经分选直接进行荧光原位杂交(D-FISH)检测和CD138免疫磁珠分选结合荧光原位杂交(MACS-FISH)检测对多发性骨髓瘤(MM)患者细胞遗传学分析的影响。.回顾性分析229例初发MM患者的FISH检测结果,一组为140例采用D-FISH法,另一组为89例采用MACS-FISH法,设计探针组合为P53、D13S319、RB1、1q21和IgH,比较两组间细胞遗传学检测结果。.D-FISH组遗传学异常总检出率为52.9%,MACS-FISH组总检出率为79.8%,两组间的细胞遗传学异常检出率比较存在显著性差异(P=0.020);两组中检出率最高的细胞遗传学异常基因分别为1q21和IgH,检出率最低的为P53;两组间P53阳性细胞率比较无显著性差异,而D13S319、RB1、1q21和IgH阳性细胞率比较均存在显著性差异(P=0.0002,P<0.0001,P=0.0033,P=0.0032)。D-FISH组骨髓细胞形态学检测浆细胞比例与遗传学异常检出率无显著相关性,而流式细胞术检测浆细胞比例与遗传学异常检出率存在相关性(r=0.364)。MACS-FISH组骨髓细胞形态学和流式细胞术检测浆细胞比例与5种基因的检出率及阳性细胞率均无相关性。骨髓细胞形态学与流式细胞术的浆细胞比例检测结果存在显著性差异(P<0.0001)。.CD138免疫磁珠分选技术结合FISH能显著提高MM细胞遗传学异常的检出率。.