比色法检测C1抑制物功能及其在遗传性血管水肿诊断中的应用

摘要

Objective to determine the C1 inhibitor function by using colorimetric method- Sensitivity and Specificity in the diagnosis of hereditary angioedema and the impact of the storage condition of the blood sample on the results were evaluated Methods The excess residual C1-esterase which formed complex with C1 inhibitor was detected by photometrical reaction with the new chromogenic substrate ( C2H5CO-Lys-Gly-Arg-pNA). Normal value was determined by detecting the plasma samples from 65 healthy volunteers. The sensitivity and specificity were also evaluated by detecting healthy volunteers and the patients with confirmed diagnosis of hereditary angioedema. Samples from 9 healthy controls were divided into 7 groups and stored at different temperatures (room temperature、 4℃、 - 20℃ ) for different durations (at prime tense, 4 h、 8 h and 24 h) and C1 inhibitor function were detected respectively, for evaluating the impact factors. Results The normal value of functional C1 INH was (0. 56-1. 58) U C1 INH/ml by colorimetric method. The sensitivity and specificity were both 100%. The bio-activity of C1 INH could be influenced by storage durations and temperature. Conclusions Colorimetric method is an effective method to determine thernC1 inhibitor function, and sensitivity and specificity was hoth really high for diangnosis of HAE. THE samplesrnshould be prepared and stored at - 20℃ immediately,otherwise it will be resulted in false positive result.%目的 采用比色法检测C1抑制物功能并评价此方法 对诊断遗传性血管水肿(hereditary angioedema,HAE)的敏感性和特异性,以及标本的储存时间和温度对检测结果 的影响.方法 将血浆标本加入过量的C1酯酶中,然后加入染色底物C2H5CO-Lys-Gly-Arg-pNA,与剩余的C1酯酶发生反应,通过分光光度仪检测与受试者血浆反应后剩余的C1酯酶与底物反应的吸光度,得出C1 INH的功能活性.通过对65名健康对照者和21例已明确诊断的HAE患者C1抑制物功能的检测,得出该方法 的正常值范围以及在HAE诊断中的敏感性和特异性.同时将9份健康对照者血浆样本分别存放于不同的温度(室温、4℃、-20℃)和时间(收集血浆后立即、4、8和24h),评价标本存放时间和温度对检测结果 的影响.结果 比色法检测C1抑制物的正常范围为(0.56~1.58)U C1 INHml,诊断HAE的特异性(6565)和敏感性(2121)均为100%.室温保存24h后,C1INH功能检测会显著下降;保存于-20℃,对检测结果 无影响.结论 比色法检测C1抑制物功能对HAE的诊断具有极高的敏感性和特异性,但易受标本保存的温度和时间影响.推荐采血后立即分离血浆检测,或存放于-20℃ 24h或以内检测,否则可能产生假阳性结果.