Liang Shaocong, Deng Guihua, Zhou Shaosong, Zeng Jing, Tan Weiqing, Yuan Xiaopeng
Department of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, GuangZhou, GuangDong, China.
J Clin Lab Anal. 2018 Mar;32(3). doi: 10.1002/jcla.22287. Epub 2017 Jun 26.
Fourth-generation HIV assays have been implemented worldwide as a screening test for many years. Understanding the performance of fourth-generation assay in low HIV prevalence region is pivotal to interpret the test result correctly. In this study, retrospective analysis was used to evaluate application of the Elecsys HIV combi PT assay.
A total of 85 043 specimens from a low prevalence setting were detected between June 2013 and October 2015. We evaluated the false-positive rate (FPR), specificity, and positive predictive value (PPV).
The specificity between male and female were 99.85% and 99.82%, respectively. The PPV on male (50.75%) was higher than female (17.05%) significantly, while the FPR was 0.15% and 0.18%. The gap between false-positive (median: 1.83, [IQR]: 1.30, 3.38) and confirmed-positive (median: 407.5, [IQR]: 184.2, 871.7) is enormous. The highest s/co ratio for false-positive cases was 85.45, while the lowest s/co ratio for confirmed-positive cases was 59.68. Various reasons were attributed to false-positive cases.
Optimal cutoff value is needed to be set to reduce the false-positive cases and predict the final status of HIV infection reliably. Retrospective analysis will help us to understand more about diagnosis of HIV.
多年来，第四代HIV检测试剂已在全球范围内用作筛查测试。了解第四代检测试剂在HIV低流行地区的性能对于正确解读检测结果至关重要。在本研究中，采用回顾性分析来评估电化学发光免疫分析法检测HIV组合抗原抗体（Elecsys HIV combi PT assay）的应用情况。
2013年6月至2015年10月期间，对来自低流行地区的85043份样本进行了检测。我们评估了假阳性率（FPR）、特异性和阳性预测值（PPV）。
男性和女性的特异性分别为99.85%和99.82%。男性的PPV（50.75%）显著高于女性（17.05%），而FPR分别为0.15%和0.18%。假阳性（中位数：1.83，[四分位间距]：1.30，3.38）与确诊阳性（中位数：407.5，[四分位间距]：184.2，871.7）之间的差距巨大。假阳性病例的最高s/co比值为85.45，而确诊阳性病例的最低s/co比值为59.68。假阳性病例存在多种原因。
需要设定最佳临界值以减少假阳性病例，并可靠地预测HIV感染的最终状态。回顾性分析将有助于我们更多地了解HIV的诊断。
