目的 应用电化学发光免疫分析法(ECLIA)和化学发光免疫测定法(CLIA)测定24小时尿游离皮质醇(UFC)，比较方法的相关性，拟用ECLIA替代CLIA检测UFC，并对ECLIA进行系统评价及建立本实验室的参考区间。方法 采用ECLIA萃取法和CLIA萃取法检测24例住院患者24小时尿液，对其结果进行相关性比较。收集87例正常人24小时尿液，用ECLIA检测其尿中游离皮质醇含量，建立参考区间，验证其系统性能，包括精密度、功能灵敏度和分析测量线性范围。结果 ECLIA萃取法和CLIA萃取法比较 r =0.9724，P<0.001，两者有相关性；ECLIA萃取法批内差异高值3.30%，低值4.52%，批间差异高值4.69%，低值6.55%；分析测量范围：0.053~58.91μg/dL,r2=0.9882, Y=1.0344X+0.8466；功能灵敏度为0.05μg/dL；以第97.5%位数为参考上限，第2.5%位数为参考下限，建立的参考区间为30.1～129.1μg/24h。结论 ECLIA萃取法具有合适的精密度、线性，可准确反映机体24小时尿游离皮质醇的分泌情况。

Objective To verify the methodology of electrochemical luminescence immunoassay (ECLIA) for determination of 24 hours urinary free cortisol. Methods The 24 hours urinary free cortisol levels in 24 in-patients were determined by using ECLIA and CLIA extraction methods respectively. The 24 hours urine of 87 health controls were collected and the free cortisol levels were measured with ECLIA. The imprecision, function sensitivity and analytical measurement range of ECLIA were verified and reference range was established. Results There were positively correlations between ECLIA and CLIA exactions in the determination of 24 hours urinary free cortisol (r=0.9724, P<0.001). The high and low values of within-run imprecision of ECLIA were 3.30% and 4.52%, and between-day imprecision were 4.69% and 6.55% respectively. The analytical measurement range was 0.053~58.91μg/dL (r2=0.9882, y=1.0344x+0.8466) and the function sensitivity was 0.05 μg/dL. The reference range of 24 hours urinary free cortisol was 30.1-129.1 μg. Conclusion The electrochemical luminescence immunoassay of urinary free cortisol has appropriate imprecision, and it could indicate the secretion of 24 hours free cortisol in urine.