Hans Lucia, Marins Ed G, Simon Christian O, Magubane Dieketseng, Seiverth Britta, Carmona Sergio
University of the Witwatersrand, School of Pathology, Department of Molecular Medicine and Haematology, Johannesburg, South Africa; National Health Laboratory Service, Johannesburg, South Africa.
Roche Molecular Systems, Inc., Pleasanton, United States.
J Clin Virol. 2021 Jul;140:104839. doi: 10.1016/j.jcv.2021.104839. Epub 2021 Apr 23.
Measurement of HIV-1 viral load (VL) is essential for monitoring antiretroviral treatment (ART) efficacy. In remote settings, dried blood spots (DBS) may be used as the specimen type. However, cellular components in DBS not present in the gold standard specimen type, plasma, may result in low specificity i.e., over-estimation of VL results from DBS compared to plasma. The Abbott RealTime HIV-1 assay system has been reported to have improved specificity using DBS compared to other tests. A new specimen collection matrix, the cobas plasma separation card (PSC, Roche Molecular Systems), enables specimen collection from a finger prick or venous blood, using a multi-layer absorption and filtration design that results in a specimen similar to plasma.
We performed a direct comparison between VL results from PSC tested with the cobas 6800/8800 assay (c8800) and DBS tested with the Abbott RealTime HIV-1 assay.
Overall concordance between PSC and plasma around the 1000 copies/mL threshold was high (>97%). Compared to VL measured using DBS and the RealTime assay, PSC and c8800 showed improved sensitivity (96.9% vs 90.6%) and specificity (97.4% vs. 87.2%) using plasma as the reference, as there were fewer patients with VL below 1000 copies/mL in plasma in whom VL was over this threshold using PSC compared to DBS. The limit of detection for PSC was lower than for DBS (575 vs. 2314 copies/mL).
cobas PSC represents a promising specimen type for use with the cobas 6600/8800 system in settings where plasma cannot be used.
测量HIV-1病毒载量（VL）对于监测抗逆转录病毒治疗（ART）疗效至关重要。在偏远地区，干血斑（DBS）可作为标本类型使用。然而，DBS中的细胞成分在金标准标本类型血浆中不存在，这可能导致特异性较低，即与血浆相比，DBS的VL结果被高估。据报道，与其他检测方法相比，雅培实时HIV-1检测系统使用DBS时特异性有所提高。一种新的标本采集基质，即cobas血浆分离卡（PSC，罗氏分子系统公司），可通过手指穿刺或静脉采血进行标本采集，采用多层吸收和过滤设计，得到类似于血浆的标本。
我们对用cobas 6800/8800检测系统（c8800）检测的PSC和用雅培实时HIV-1检测法检测的DBS的VL结果进行了直接比较。
在1000拷贝/毫升阈值附近，PSC与血浆之间的总体一致性较高（>97%）。与使用DBS和实时检测法测量的VL相比，以血浆为参照，PSC和c8800显示出更高的灵敏度（96.9%对90.6%）和特异性（97.4%对87.2%），因为与DBS相比，血浆中VL低于1000拷贝/毫升但使用PSC时VL超过此阈值的患者较少。PSC的检测限低于DBS（575对2314拷贝/毫升）。
在无法使用血浆的情况下，cobas PSC是一种有前景的标本类型，可与cobas 6600/8800系统配合使用。
