University of Health Sciences, Sultan 2. Abdulhamid Han Training and Research Hospital, Department of Infectious Diseases and Clinical Microbiology - İstanbul, Turkey.
Gülhane Training and Research Hospital, Regional Blood Center - Ankara, Turkey.
Rev Assoc Med Bras (1992). 2024 Sep 2;70(8):e20240370. doi: 10.1590/1806-9282.20240370. eCollection 2024.
In the hepatitis C virus (HCV) diagnostic algorithm, an anti-HCV screening test is recommended first. In countries with low HCV prevalence, anti-HCV testing can often give false-positive results. This may lead to unnecessary retesting, increased costs, and psychological stress for patients.
In this study, the most appropriate S/Co (signal-cutoff) value to predict HCV viremia in anti-HCV test(+) individuals was determined, and the effect of genotype differences was evaluated. Of the 96,515 anti-HCV tests performed between 2020 and 2023, 934 were reactive. A total of 332 retests and 65 patients without HCV-ribonucleic acid (RNA) analysis were excluded. Demographic data were calculated for 537 patients, and 130 patients were included in the study.
The average age of 537 patients was 55±18 years, and 57.1% were women. The anti-HCV positivity rate was 0.62% (602/96,515), and the actual anti-HCV positivity rate was 0.13% (130/96,515). Anti-HCV levels were higher in HCV-RNA(+) patients than in HCV-RNA-negative individuals (p<0.0001) (Table 1). Receiver operating characteristic curve analysis identified the optimal S/Co value to be 10.86 to identify true positive cases. Sensitivity was 96.1%, specificity was 61.2%, positive predictive value (PPV) was 44.2%, and negative predictive value (NPV) was 98% (Figure 2). A total of 107 (82.3%) of the patients were identified as GT1, and the most common subtype was GT1b (n=100).
If anti-HCV S/Co is ≥10.86, direct HCV RNA testing may be recommended; However, the possibility of false positivity should be considered in patients with a S/Co value below 10.86.
在丙型肝炎病毒（HCV）诊断算法中，建议首先进行抗 HCV 筛查检测。在 HCV 流行率较低的国家，抗 HCV 检测通常会出现假阳性结果。这可能导致不必要的重复检测、增加成本，并给患者带来心理压力。
在这项研究中，确定了最适合预测抗 HCV 检测(+)个体 HCV 病毒血症的 S/Co（信号-截止）值，并评估了基因型差异的影响。在 2020 年至 2023 年期间进行的 96515 次抗 HCV 检测中，有 934 次呈反应性。共有 332 次重复检测和 65 例未进行 HCV-核糖核酸（RNA）分析的患者被排除在外。对 537 例患者的人口统计学数据进行了计算，其中 130 例患者纳入研究。
537 例患者的平均年龄为 55±18 岁，57.1%为女性。抗 HCV 阳性率为 0.62%（602/96515），实际抗 HCV 阳性率为 0.13%（130/96515）。HCV-RNA(+)患者的抗 HCV 水平高于 HCV-RNA 阴性个体（p<0.0001）（表 1）。受试者工作特征曲线分析确定最佳 S/Co 值为 10.86 以识别真正的阳性病例。灵敏度为 96.1%，特异性为 61.2%，阳性预测值（PPV）为 44.2%，阴性预测值（NPV）为 98%（图 2）。共发现 107 例（82.3%）患者为 GT1 型，最常见的亚型为 GT1b（n=100）。
如果抗 HCV S/Co 值≥10.86，则建议直接进行 HCV RNA 检测；然而，对于 S/Co 值低于 10.86 的患者，应考虑假阳性的可能性。
