Division of Clinical Microbiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland.
Blood Transfusion Centre, Swiss Red Cross, Hebelstrasse 10, 4056 Basel, Switzerland.
J Virol Methods. 2017 Nov;249:143-146. doi: 10.1016/j.jviromet.2017.09.005. Epub 2017 Sep 8.
This study aimed at assessing the specificity of the Elecsys HIV combi PT in comparison to the ARCHITECT HIV Ag/Ab Combo. With both of these assays, 3997 unselected sera from patients of a tertiary health care centre in Basel, Switzerland, were screened for HIV. Reactive sera were reanalysed on the VIDAS HIV Duo Ultra to identify false-reactive specimens prior to confirmation by quantitative PCR and line immunoassay. The Elecsys compared to the ARCHITECT shows a similar specificity (99.7% versus 99.8%) but a slightly lower positive predictive value (71.8% versus 80%). Samples tested with a cut-off index (COI) between 0.91 and 4.85 (cut-off <0.9) with the Elecsys and with a signal to cut-off index (S/CO) between 1.09 and 12.49 (cut-off <1.0) with the ARCHITECT were false-reactive. There was no false-reactive result with the VIDAS. Of the false-reactive samples, 66.7% could be related to patient-specific underlying conditions. The HIV two-tiered diagnostic algorithm proposed in this work improved the positive predictive values of the Elecsys or ARCHITECT to 100% when the results of the VIDAS were included. Values just above the cut-off are highly suspicious to be false-reactive and high COI or S/CO ratios are associated with true positivity.
本研究旨在评估 Elecsys HIV combi PT 与 ARCHITECT HIV Ag/Ab Combo 的特异性。使用这两种检测方法，对瑞士巴塞尔一家三级保健中心的 3997 份未经选择的患者血清进行了 HIV 筛查。对反应性血清进行 VIDAS HIV Duo Ultra 重新分析，以在通过定量 PCR 和线免疫测定确认之前识别假反应性标本。与 ARCHITECT 相比，Elecsys 的特异性相似（99.7%对 99.8%），但阳性预测值略低（71.8%对 80%）。用 Elecsys 检测到的 cutoff 指数（COI）在 0.91 到 4.85 之间（cutoff <0.9）和用 ARCHITECT 检测到的信号与 cutoff 指数（S/CO）在 1.09 到 12.49 之间（cutoff <1.0）的样本为假反应性。VIDAS 无假反应性结果。假反应性样本中，66.7%可能与患者特定的基础疾病有关。当包括 VIDAS 的结果时，本研究提出的 HIV 两步诊断算法将 Elecsys 或 ARCHITECT 的阳性预测值提高到 100%。接近 cutoff 值的结果高度怀疑为假反应性，高 COI 或 S/CO 比值与真正的阳性相关。
