ELISA双抗体夹心法检测嗜铬蛋白A的性能评价及临床应用

摘要

目的 验证酶联免疫吸附试验(ELISA)双抗体夹心法检测嗜铬蛋白A(CgA)的性能,评价其初步的临床应用价值.方法 方法学验证参考美国临床实验室标准化协会(CLSI)EP15-A、EP6-A和EP17-A文件,对项目的精密度、线性和定量检测下限进行验证.采用厂商提供的质控品验证正确度.检测66例神经内分泌肿瘤患者、41名健康对照者和65例疾病对照患者的CgA水平,采用受试者工作特征(ROC)曲线评估CgA对神经内分泌肿瘤患者的诊断能力.结果 ELISA双抗体夹心法检测血清CgA的批内变异系数(CV)<14.00％、批间CV<8.00％;正确度验证测定值的均值在标示浓度范围内,相对偏移为4.51％;在8～740 ng/mL的范围内线性良好(Y=0.793X-3.791,r2=0.988);定量检测下限为7.93 ng/mL.神经内分泌肿瘤组、健康对照组和疾病对照组之间血清CgA水平差异均有统计学意义(P<0.0001);CgA鉴别正常人与神经内分泌肿瘤患者的ROC曲线下面积(AUC)为0.741,最佳诊断界值为47.18 ng/mL,诊断敏感性为78.8％,特异性为68.3％.结论 ELISA双抗体夹心法检测CgA试剂盒具有良好的精密度、正确度、线性范围和定量检测下限,检测性能符合临床要求.血清CgA水平在神经内分泌肿瘤患者中显著升高,因此可用于鉴别健康人和神经内分泌肿瘤患者.%Objective To evaluate the performance of double-antibody sandwich enzyme-linked immunosorbent assay (ELISA)for chromogranin A (CgA)determination. Methods The precision,linearity and limit of determination of CgA determination by double-antibody sandwich ELISA were verified according to the Clinical and Laboratory Standards Institute (CLSI) EP15-A,EP6-A and EP17-A. The accuracy of CgA determination was assessed by manufacturer's quality control materials. A total of 66 neuroendocrine neoplasm patients,41 healthy subjects and 65 disease control patients were enrolled. The CgA levels in the 3 groups were determined, and receiver operating characteristic (ROC) curve was used to compare the efficiency of CgA determination in diagnosing neuroendocrine neoplasm. Results The within-run and between-run coefficients of variation (CV) of CgA determination by double-antibody sandwich ELISA were <14.00％ and <8.00％,respectively. For accuracy evaluation,the relative bias was 4.51％,when the mean of results was within the indicated range. There was a good linear correlation(Y=0.793X-3.791,r2=0.988) in the range of 8-740 ng/mL. The limit of determination was 7.93 ng/mL. The difference of CgA levels in neuroendocrine neoplasm,healthy control and disease control groups had statistical significance (P<0.0001). The area under curve(AUC)of CgA determination in distinguishing healthy subjects and neuroendocrine neoplasm patients was 0.741,when the cut-off value was 47.18 ng/mL. The sensitivity was 78.8％,and the specificity was 68.3％. Conclusions CgA determination by double-antibody sandwich ELISA has good performance in precision,accuracy,linearity and limit of determination,which meets clinical needs. Serum CgA levels increase in patients with neuroendocrine neoplasm. CgA could be a marker for distinguishing healthy subjects and neuroendocrine neoplasm patients.