Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Hepatitis, STD, and TB Prevention, Atlanta, GA 30333, USA.
J Clin Virol. 2011 Dec;52 Suppl 1:S17-22. doi: 10.1016/j.jcv.2011.09.011. Epub 2011 Oct 5.
The current algorithm for HIV diagnosis in the US involves screening with an immunoassay (IA) and supplemental testing with Western blot (WB) or immunofluorescence assay. Because of existence of more sensitive and specific FDA-approved assays that would also reduce the cost and turn-around time of testing compared to WB, several alternative algorithms have been evaluated. Recently, an alternative algorithm using a sensitive 3rd or 4th generation IA followed by an HIV-1 and HIV-2 discriminatory supplemental test on the initial IA-positive specimens was proposed. Concordant positive results indicate HIV-positive specimens and discordant results are resolved by nucleic acid amplification testing (NAAT).
To evaluate the sensitivity of assays during acute HIV infection and the performance of the current and an alternative algorithm using samples from HIV-1 seroconversion panels and persons with established HIV infections.
To evaluate the algorithms in early infections, 26 HIV-1 seroconverters from the US were tested with three 3rd generation and one 4th generation IA, six rapid tests (RTs), one NAAT, and WB. Sensitivity and specificity of the algorithms were calculated by testing an additional 416 HIV-positive and 414 uninfected control samples with one 3rd generation and one 4th generation IA, four RTs, one NAAT, and WB.
The individual assays evaluated became positive 5 (RT) to 26 days (NAAT) before WB was positive. Among seroconverters, the alternative algorithm detected significantly more infections than the current algorithm (103-134 versus 56, p<0.0001). Furthermore, the use of a 4th generation IA instead of a 3rd generation assay as the screen resulted in significantly higher detection of acute infections (p<0.0001). In contrast, the algorithms performed equally among specimens from established HIV-1 infections.
This study demonstrated improved sensitivity of the alternative algorithm for detecting acute HIV-1 infections, while maintaining the ability to accurately detect established HIV-1 infections. Early detection is important as individuals can be highly infectious during acute infection. In addition, the alternative algorithm should reduce turn-around time by using a RT as the supplemental test has the potential to increase the number of test results returned.
目前美国的 HIV 诊断算法包括使用免疫分析（IA）进行筛查，以及使用 Western blot（WB）或免疫荧光分析（IFA）进行补充检测。由于存在更敏感和特异的已获 FDA 批准的检测方法，与 WB 相比，这些方法还可以降低检测成本和周转时间，因此已经评估了几种替代算法。最近，提出了一种替代算法，即在初始 IA 阳性标本上使用敏感的第三代或第四代 IA，然后进行 HIV-1 和 HIV-2 鉴别性补充检测。一致的阳性结果表明 HIV 阳性标本，不一致的结果通过核酸扩增检测（NAAT）解决。
评估在急性 HIV 感染期间检测方法的敏感性，并使用来自 HIV-1 血清转换面板和已建立的 HIV 感染者的样本评估当前和替代算法的性能。
为了评估早期感染中的算法，用三种第三代和一种第四代 IA、六种快速检测（RT）、一种 NAAT 和 WB 检测了来自美国的 26 名 HIV-1 血清转换者。通过用一种第三代和一种第四代 IA、四种 RT、一种 NAAT 和 WB 检测另外 416 份 HIV 阳性和 414 份未感染对照样本，计算了算法的敏感性和特异性。
各检测方法在 WB 阳性前 5 天（RT）至 26 天（NAAT）时开始阳性。在血清转换者中，替代算法检测到的感染明显多于当前算法（103-134 比 56，p<0.0001）。此外，使用第四代 IA 而不是第三代 IA 作为筛查方法可显著提高急性感染的检出率（p<0.0001）。相比之下，在来自已建立的 HIV-1 感染的标本中，算法的性能相当。
本研究表明，替代算法在检测急性 HIV-1 感染方面具有更高的敏感性，同时保持了准确检测已建立的 HIV-1 感染的能力。早期检测很重要，因为个体在急性感染期间可能具有高度传染性。此外，替代算法通过使用 RT 作为补充检测，可以减少周转时间，因为该方法有可能增加返回的检测结果数量。
