目的：了解血清CYFRA21－1在非小细胞肺癌（NSCLC）中的诊断价值以及化疗后其水平的变化。方法：采用放射免疫法测定非小细胞肺癌患者化疗前后血清CYFRA21－1水平。结果：非小细胞肺癌患者血清CYFRA21－1水平（13．95±19．91ng／ml）远高于非肿瘤组(1.27±1．1ng／ml）（P＜0．001）；而化疗前后CYFRA21－1水平的变化无显著性差异。结论：血清CYFRA21－1是诊断非小细胞肺癌一种敏感、可靠的指标，且不受化疗因素的影响。 Objective: To understand the diagnostic value of serum CYFRA21-1 in non-small cell lung cancer (NSCLC) and its level after chemotherapy. Methods: Serum CYFRA21-1 levels in patients with NSCLC before and after chemotherapy were measured by radioimmunoassay. Results: Serum CYFRA21-1 levels in patients with non-small cell lung cancer (13.95±19.91 ng/ml) were significantly higher than those in the non-tumor group (1.27±1.1 ng/ml) (P<0.001); before and after chemotherapy, CYFRA21 There was no significant difference in changes in -1 levels. Conclusion: Serum CYFRA21-1 is a sensitive and reliable indicator for the diagnosis of non-small cell lung cancer, and it is not affected by chemotherapy.