Division of Infectious Diseases, Department of Medicine, University of North Carolina, Chapel Hill.
School of Medicine, University of North Carolina, Chapel Hill.
Clin Infect Dis. 2018 Jan 6;66(2):254-260. doi: 10.1093/cid/cix771.
Efficient viral load testing is needed for hepatitis C (HCV) surveillance and diagnosis. HCV viral load testing using dried blood spots (DBSs), made with a single drop of finger-prick whole blood on filter paper, is a promising alternative to traditional serum- or plasma-based approaches.
We adapted the Abbott Molecular m2000 instrument for high-throughput HCV viremia testing using DBSs with simple specimen processing and applied these methods to estimate the national burden of infection in the Democratic Republic of the Congo (DRC). We tested DBSs collected during the 2013-2014 DRC Demographic and Health Survey, including 1309 adults ≥40 years of age. HCV-positive samples underwent targeted sequencing, genotyping, and phylogenetic analyses.
This high-throughput screening approach reliably identified HCV RNA extracted from DBSs prepared using whole blood, with a 95% limit of detection of 1196 (95% confidence interval [CI], 866-2280) IU/mL for individual 6-mm punches and 494 (95% CI, 372-1228) IU/mL for larger 12-mm punches. Fifteen infections were identified among samples from the DRC Demographic and Health Survey; the weighted country-wide prevalence of HCV viremia was 0.9% (95% CI, 0.3%-1.6%) among adults ≥40 years of age and 0.7% (95% CI, .6%-.8%) among human immunodeficiency virus-infected subjects. All successfully genotyped cases were due to genotype 4 infection.
DBS-based HCV testing represents a useful tool for the diagnosis and surveillance of HCV viremia and can easily be incorporated into specimen referral systems. Among adults ≥40 years of age in the DRC, 100000-200000 may have active infection and be eligible for treatment.
高效的病毒载量检测对于丙型肝炎（HCV）监测和诊断至关重要。使用滤纸上一滴指血制成的干血斑（DBS）进行 HCV 病毒载量检测，是一种有前途的替代传统基于血清或血浆方法的方法。
我们对 Abbott Molecular m2000 仪器进行了改编，用于使用 DBS 进行高通量 HCV 血症检测，方法简单，适用于处理标本，并应用这些方法来估计刚果民主共和国（DRC）的感染负担。我们测试了 2013-2014 年 DRC 人口与健康调查中收集的 DBS，包括 1309 名≥40 岁的成年人。HCV 阳性样本进行了靶向测序、基因分型和系统发育分析。
这种高通量筛选方法可靠地识别了从使用全血制备的 DBS 中提取的 HCV RNA，对于单个 6mm 打孔，95%检测限为 1196（95%置信区间 [CI]，866-2280）IU/ml，对于较大的 12mm 打孔，95%检测限为 494（95%CI，372-1228）IU/ml。在 DRC 人口与健康调查的样本中发现了 15 例感染；≥40 岁成年人中丙型肝炎病毒血症的全国加权流行率为 0.9%（95%CI，0.3%-1.6%），人类免疫缺陷病毒感染人群为 0.7%（95%CI，.6%-.8%）。所有成功基因分型的病例均归因于基因型 4 感染。
基于 DBS 的 HCV 检测代表了诊断和监测 HCV 血症的有用工具，并且可以很容易地纳入标本转诊系统。在 DRC 中≥40 岁的成年人中，可能有 100000-200000 人患有活动性感染，有资格接受治疗。
