Fajardo Emmanuel, Metcalf Carol A, Chaillet Pascale, Aleixo Lucia, Pannus Pieter, Panunzi Isabella, Triviño Laura, Ellman Tom, Likaka Andrew, Mwenda Reuben
Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa.
J Clin Microbiol. 2014 May;52(5):1343-51. doi: 10.1128/JCM.03519-13. Epub 2014 Feb 5.
HIV-1 viral load (VL) testing is not widely available in resource-limited settings. The use of finger prick dried blood spot (FP-DBS) samples could remove barriers related to sample collection and transport. Measurement of VL using DBS from EDTA venous blood (VB-DBS) in place of plasma has previously been validated using the NucliSENS Easy-Q HIV-1 v2.0 assay, but information on the accuracy of FP-DBS samples for measuring VL is limited. This prospective study, conducted at Thyolo District Hospital in southern Malawi, compared VL levels measured on FP-DBS samples and plasma using the NucliSENS Easy-Q HIV-1 v2.0 assay. Comparability was assessed by means of agreement and correlation (131 patients with VLs of ≥100 copies/ml), sensitivity, and specificity (612 patients on antiretroviral treatment [ART]). Samples of EDTA venous blood and FP-DBS from 1,009 HIV-infected individuals were collected and prepared in the laboratory. Bland-Altman analysis found good agreement between plasma and FP-DBS VL levels, with a mean difference of -0.35 log10, and 95% limits of agreement from -1.26 to 0.55 log10. FP-DBS had a sensitivity of 88.7% (95% confidence interval [CI], 81.1 to 94.4%) and a specificity of 97.8% (95% CI, 96.1 to 98.9%) using a 1,000-copies/ml cut point and a sensitivity of 83.0% (95% CI, 73.4 to 90.1%) and a specificity of 100% (95% CI, 99.3 to 100%) using a 5,000-copies/ml cut point. This study shows that FP-DBS is an acceptable alternative to plasma for measuring VL using the NucliSENS Easy-Q HIV-1 v2.0. We are conducting a second study to assess the proficiency of health workers at preparing FP-DBS in primary health care clinics.
在资源有限的环境中，HIV-1病毒载量（VL）检测尚未广泛普及。使用手指针刺干血斑（FP-DBS）样本可以消除与样本采集和运输相关的障碍。此前已使用NucliSENS Easy-Q HIV-1 v2.0检测法验证了使用乙二胺四乙酸静脉血（VB-DBS）的干血斑代替血浆来测量病毒载量，但关于FP-DBS样本测量病毒载量准确性的信息有限。这项前瞻性研究在马拉维南部的蒂约洛区医院进行，比较了使用NucliSENS Easy-Q HIV-1 v2.0检测法在FP-DBS样本和血浆上测得的病毒载量水平。通过一致性和相关性（131名病毒载量≥100拷贝/毫升的患者）、敏感性和特异性（612名接受抗逆转录病毒治疗[ART]的患者）进行可比性评估。收集了1009名HIV感染者的乙二胺四乙酸静脉血样本和FP-DBS样本，并在实验室中进行制备。Bland-Altman分析发现血浆和FP-DBS病毒载量水平之间具有良好的一致性，平均差异为-0.35 log10，95%一致性界限为-1.26至0.55 log10。使用1000拷贝/毫升的截断点时，FP-DBS的敏感性为88.7%（95%置信区间[CI]，81.1至94.4%），特异性为97.8%（95% CI，96.1至98.9%）；使用5000拷贝/毫升的截断点时，敏感性为83.0%（95% CI，73.4至90.1%），特异性为100%（95% CI，99.3至100%）。这项研究表明，对于使用NucliSENS Easy-Q HIV-1 v2.0测量病毒载量而言，FP-DBS是血浆的可接受替代物。我们正在开展第二项研究，以评估初级卫生保健诊所的卫生工作者制备FP-DBS的熟练程度。
