目的　探讨染色体检查在鉴别恶性肿瘤患者合并的胸腹水有无癌细胞中的作用。方法　对确诊恶性肿瘤的患者出现胸腹水后 ,留取胸腹水标本同时送检染色体、细胞学和DNA检查 ,对 2种检查结果进行常规和 1∶2配比分析。结果　脱落细胞学检查阳性率 71 .8% ,DNA分析阳性率 56.3 % ,染色体检查阳性率 93.8% ,统计学分析存在显著差异 (p <0 .0 1 ) ,进一步进行 1∶2配比分析 ,计算比值比 (OR)为 +∞。结论　染色体检查对鉴别良恶性胸腹水有重要意义 ,且优于细胞学检查和DNA分析 Objective To investigate the role of chromosome examination in the differential diagnosis of malignant tumor patients with or without cancerous cells. Methods After pleural effusion and ascites occurred in patients diagnosed with malignant tumors, samples of pleural effusion and ascites were collected for chromosome, cytology and DNA examinations. Routine and 1:2 ratio analyses were performed on the results of the two tests. Results The positive rate of cytology was 71.8%, the positive rate of DNA analysis was 56.3%, and the positive rate of chromosome examination was 93.8%. There was a statistically significant difference (p<0.01), and a further 1:2 ratio analysis was performed. Calculate the odds ratio (OR) to +∞. Conclusion Chromosomal examination is of great significance for the differentiation of benign and malignant pleural effusions and is superior to cytology and DNA analysis.