Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, CA, USA.
Clin Chem. 2011 Jul;57(7):1050-6. doi: 10.1373/clinchem.2010.158691. Epub 2011 May 12.
Chemiluminescence immunoassay (CIA) is used to detect hepatitis C virus (HCV) antibody status on the basis of signal-to-cutoff (S/Co) ratios. Positive results of antibody to HCV (anti-HCV) are followed by either recombinant immunoblot assay (RIBA) to confirm anti-HCV positivity or reverse transcription (RT)-PCR to detect viremia. We hypothesized that by analyzing S/Co ratios, we could determine a strategy to reduce unnecessary supplementary testing in our population.
CIA was performed to screen for anti-HCV, and positive results were followed up with RT-PCR testing. Negative RT-PCR results were followed up with RIBA, whereas positive RT-PCR results were assumed to be RIBA positive. ROC curves were analyzed to determine the optimal S/Co ratios to predict HCV infection.
We determined the S/Co ratios on 34 243 veteran patient samples. We found that with the CIA method 9.0% of patients had positive test results for anti-HCV. An S/Co ratio <3.0 ruled out active HCV infection and exposure with 100% negative predictive value. When the S/Co ratio was ≥20.0, positive predictive values were 98.5% compared with RIBA results, and 81.0% compared with RT-PCR results.
RIBA is not necessary to confirm negative or positive CIA anti-HCV if the S/Co ratio is <3.0 or ≥20.0, respectively. To confirm HCV exposure, samples with an S/Co ratio between 3.0 and 19.9 should be followed up with RIBA unless PCR testing has been performed and the result is positive. Samples with an S/Co ratio ≥20.0 or positive RIBA results should be further tested by RT-PCR to determine HCV viremia status.
化学发光免疫分析（CIA）用于根据信号与临界值（S/Co）比值检测丙型肝炎病毒（HCV）抗体状态。抗 HCV（抗-HCV）的阳性结果随后进行重组免疫印迹分析（RIBA）以确认抗-HCV 阳性，或进行逆转录（RT）-PCR 以检测病毒血症。我们假设通过分析 S/Co 比值，可以确定在我们的人群中减少不必要的补充检测的策略。
CIA 用于筛查抗-HCV，阳性结果随后进行 RT-PCR 检测。阴性 RT-PCR 结果随后进行 RIBA 检测，而阳性 RT-PCR 结果假定为 RIBA 阳性。ROC 曲线用于分析确定预测 HCV 感染的最佳 S/Co 比值。
我们确定了 34243 名退伍军人患者样本的 S/Co 比值。我们发现，使用 CIA 方法，9.0%的患者抗-HCV 检测结果阳性。S/Co 比值<3.0 排除了 HCV 感染和暴露的可能性，阴性预测值为 100%。当 S/Co 比值≥20.0 时，与 RIBA 结果相比，阳性预测值为 98.5%，与 RT-PCR 结果相比为 81.0%。
如果 S/Co 比值分别<3.0 或≥20.0，则无需 RIBA 确认 CIA 抗-HCV 的阴性或阳性。为了确认 HCV 暴露，S/Co 比值在 3.0 和 19.9 之间的样本应进行 RIBA 检测，除非已进行 PCR 检测且结果为阳性。S/Co 比值≥20.0 或 RIBA 结果阳性的样本应进一步进行 RT-PCR 检测以确定 HCV 病毒血症状态。
