丙型肝炎病毒抗体筛查阳性结果确证方案的探讨

Study on the confirmatory protocol for the positive results of hepatitis C viral antibody blood screening test

目的明确抗-HCV酶免检测结果与确证阳性结果之间的相互关系,以期建立简便、经济的血液筛查实验室抗-HCV确证试验方案。方法使用重组免疫印迹试验结合核酸检测方法对134份酶免抗-HCV阳性样本确证,初步探讨2或3种抗-HCV酶免试剂(Ortho、Murex和科华联合复检的S/Co值与阳性预期值的关系及不同试剂组合检测的阳性预期值。结果134份样本中,92份真阳性,5份可疑,其余均为阴性。Ortho和Murex试剂的S/Co与阳性预期值呈正相关,当S/Co≥3.8时,阳性预期值分别可达98.33%和97.78%。Murex联合科华、Ortho联合科华以及3种试剂同时检测为阳性时的阳性预期值为100%;Ortho联合Murex的阳性预期值为98.48%,与上述其它2或3种试剂组合比较,差异无统计学意义(P>0.05)。结论2种或3种酶免试剂联合复检的确证方案优于美国CDC推荐的S/Co≥3.8方案。在常规血液筛查实验室,可以选择3种抗-HCV试剂中的任2种同时复检,先行对抗-HCV阳性标本确证,对无法确证的样本再作重组免疫印迹试验分析。

Objective To clarify the relationship between the results of anti-HCV EIA and the confirmed positive resuits, to explore a simple and economic protocol for confirming the reactive results of hepatitis C viral antibody blood screening test. Methods HCV antibody western blot confirmatory assay （WB） and nucleic acid testing （NAT） were performed to confirm the real positive samples from 134 HCV antibody reactive samples. Ortho, Murex and Kehua HCV antibody diagnostic kits were selected to clarify the relationship between the tested Signal/Cut off ratios （ S/Co ） and the positive expectations. The positive expectations of each EIA kits and combined tests were also assessed. Results In the 134 HCV antibody reactive samples, 92 were confirmed real positive samples, 5 were indeterminate samples, and the others were negative samples. The S/Co of Ortho and Murex were positively correlated with the positive predictive value. The positive predictive values of the 2 kits were 98.33% and 97.78%, respectively, when S/Co was ≥3.8. The positive predictive value of the samples reactive to Murex ＆ Kehua, Ortho ＆ Kehua, and all 3 EIA kits together were 100%. Although the positive predictive value of Ortho ＆ Murex was 98.48%, there was no statistical difference between this group and other groups. Conclusion In blood sereening laboratory, 2 or 3 EIA kits combined test can be used together to confirm the anti-HCV reactive samples before RIBA or WB confirmatory assay. This protocol is better than that confirmed by S/Co≥3.8, which was recommended by CDC of America.