Université de Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement Travail), UMR_S 1085, 35000 Rennes, France.
Parasite. 2021;28:39. doi: 10.1051/parasite/2021035. Epub 2021 Apr 26.
Chronic infection with Toxoplasma gondii is attested by the detection of specific anti-Toxoplasma IgG. A wide panel of serologic methods is currently marketed, and the most suitable method should be chosen according to the laboratory resources and the screened population. This systematic review of evaluation studies aimed at establishing an overview of the performances, i.e. sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of marketed anti-Toxoplasma IgG assays, and discussing their technical characteristics to guide further choice for routine diagnostic use. According to PRISMA guidelines, the search performed in PubMed and Web of Science databases recovered 826 studies, of which 17 were ultimately included. Twenty commercial anti-Toxoplasma IgG assays were evaluated, in comparison with an accepted reference method. Most of them were enzyme-immunoassays (EIAs, n = 12), followed by agglutination tests (n = 4), immunochromatographic tests (n = 3), and a Western-Blot assay (WB, n = 1). The mean sensitivity of IgG assays ranged from 89.7% to 100% for standard titers and from 13.4% to 99.2% for low IgG titers. A few studies pointed out the ability of some methods, especially WB to detect IgG early after primary infection. The specificity of IgG assays was generally high, ranging from 91.3% to 100%; and higher than 99% for most EIA assays. The PPV was not a discriminant indicator among methods, whereas significant disparities (87.5%-100%) were reported among NPVs, a key-parameter assessing the ability to definitively rule out a Toxoplasma infection in patients at-risk for opportunistic infections.
慢性弓形虫感染可通过检测特异性抗弓形虫 IgG 来证实。目前市场上有广泛的血清学方法，应根据实验室资源和筛查人群选择最合适的方法。本系统评价评估研究旨在概述市售抗弓形虫 IgG 检测方法的性能，即敏感性、特异性、阳性预测值 (PPV) 和阴性预测值 (NPV)，并讨论其技术特点，以指导常规诊断用途的进一步选择。根据 PRISMA 指南，在 PubMed 和 Web of Science 数据库中进行的搜索共检索到 826 项研究，最终纳入了 17 项研究。共评估了 20 种商业抗弓形虫 IgG 检测方法，与公认的参考方法进行比较。其中大多数是酶联免疫吸附试验 (ELISA，n=12)，其次是凝集试验 (n=4)、免疫层析试验 (n=3) 和 Western-Blot 试验 (WB，n=1)。IgG 检测方法的平均敏感性对于标准滴度范围从 89.7%到 100%，对于低 IgG 滴度范围从 13.4%到 99.2%。一些研究指出，一些方法，特别是 WB，具有在初次感染后早期检测 IgG 的能力。IgG 检测方法的特异性通常较高，范围从 91.3%到 100%；对于大多数 ELISA 检测方法，特异性高于 99%。PPV 不是方法之间的鉴别指标，而 NPV 差异显著 (87.5%-100%)，NPV 是评估在机会性感染高危患者中明确排除弓形虫感染能力的关键参数。
