目的 测定多发性骨髓瘤（MM）患者血清胱抑素C （Cys-C） 的水平，探讨Cys-C与国际分期体系（ISS）、血β2-微球蛋白、溶骨性损害等指标的关系。 方法 收集2008年1月－2010年9月32例初治和8例复发的MM患者作为研究对象，同时收集40例健康体检者的检查资料作为对照组，测定血清Cys-C、血肌酐（Scr）、血β2-微球蛋白。采用核素全身骨显像（ECT）观察患者的溶骨性病变部位数。 结果 患者血清Cys-C水平（1.40 mg/L）明显高于健康对照组（0.90 mg/L）（P＜0.01）；在MM患者中Cys-C比Scr更敏感，能反映肾小球滤过率；血清Cys-C水平与ISS分期晚，血β2-微球蛋白升高以及溶骨性病变进展密切相关。 结论 MM患者的Cys-C水平高于健康者。Cys-C是骨髓瘤肾损害的早期敏感标志物，与肿瘤负荷及溶骨性损害密切相关，可作为评价肿瘤负荷的潜在指标。Objective To evaluate the serum levels of cystatin-C in patients with multiple myeloma (MM), and to explore its possible correlations with clinical data, including ISS stage, serum β2-microglobulin, and advanced lytic lesions. Methods From January 2008 to September 2010, serum cystatin-C, creatinine (Scr), and β2-microglobulin in 32 patients with MM, 8 patients with relapsed disease, and in 40 healthy controls were detected by automatic biochemistry analyzer detection. According to skeleton ECT, grading of osteolytic lesion was observed. Results The levels of serum cystatin-C of patients with MM were significantly higher than those of the controls. Serum cystatin-C could reflect the glomerular filtration rate , and was more sensitive than Scr in patients with renal lesion. Serum cystatin-C had ber correlations with advanced ISS stages, high levels of serum β2-microglobulin, and extensive bone diseases. Conclusion Serum cystatin-C is a sensitive marker of renal lesion in patients with MM, it could be a potential indicator to assess the tumor burden.