HIV-1 viral load measurement in venous blood and fingerprick blood using Abbott RealTime HIV-1 DBS assay

• Published in: Journal of clinical virology 2017-07, Vol.92, p.56-61
• Main Authors: Tang, Ning, Pahalawatta, Vihanga, Frank, Andrea, Bagley, Zowie, Viana, Raquel, Lampinen, John, Leckie, Gregor, Huang, Shihai, Abravaya, Klara, Wallis, Carole L.
• Format: Article
• Language: English
• Subjects: Adult; Blood Specimen Collection - methods; Cote d'Ivoire; Dried blood spot; Dried Blood Spot Testing; HIV Infections - diagnosis; HIV Infections - epidemiology; HIV Infections - virology; HIV-1 - genetics; HIV-1 - isolation & purification; HIV-1 - physiology; Human immunodeficiency virus; Humans; Limit of Detection; Reagent Kits, Diagnostic; Real-Time Polymerase Chain Reaction - instrumentation; Real-Time Polymerase Chain Reaction - methods; RNA, Viral - blood; Sensitivity and Specificity; Serologic Tests - methods; South Africa; Specimen Handling; Viral Load - instrumentation; Viral Load - methods; Viral load testing; Young Adult
• ISSN: 1386-6532; 1873-5967
• DOI: 10.1016/j.jcv.2017.05.002

•Dried blood spots are an alternative sample type to plasma for HIV-1 RNA quantitation.•A protocol was developed on Abbott RealTime HIV-1 to test DBS samples.•Analytical performance of the Abbott RealTime HIV-1 DBS method met WHO requirements, in particular an analytical sensitivity of ≤1000 copies/mL " to "DBS analytical sensitivity of ≤1000 copies/mL.•Good HIV-1 RNA quantitative agreement was obtained between plasma and DBS collected using venous and fingerprick methods.•The data support that DBS can be used as an alternative to plasma for HIV-1 RNA quantitation in resource limited areas. HIV RNA suppression is a key indicator for monitoring success of antiretroviral therapy. From a logistical perspective, viral load (VL) testing using Dried Blood Spots (DBS) is a promising alternative to plasma based VL testing in resource-limited settings. To evaluate the analytical and clinical performance of the Abbott RealTime HIV-1 assay using a fully automated one-spot DBS sample protocol. Limit of detection (LOD), linearity, lower limit of quantitation (LLQ), upper limit of quantitation (ULQ), and precision were determined using serial dilutions of HIV-1 Virology Quality Assurance stock (VQA Rush University), or HIV-1-containing armored RNA, made in venous blood. To evaluate correlation, bias, and agreement, 497 HIV-1 positive adult clinical samples were collected from Ivory Coast, Uganda and South Africa. For each HIV-1 participant, DBS-fingerprick, DBS-venous and plasma sample results were compared. Correlation and bias values were obtained. The sensitivity and specificity were analyzed at a threshold of 1000 HIV-1 copies/mL generated using the standard plasma protocol. The Abbott HIV-1 DBS protocol had an LOD of 839 copies/mL, a linear range from 500 to 1×107 copies/mL, an LLQ of 839 copies/mL, a ULQ of 1×107 copies/mL, and an inter-assay SD of ≤0.30 log copies/mL for all tested levels within this range. With clinical samples, the correlation coefficient (r value) was 0.896 between DBS-fingerprick and plasma and 0.901 between DBS-venous and plasma, and the bias was −0.07 log copies/mL between DBS-fingerprick and plasma and −0.02 log copies/mL between DBS-venous and plasma. The sensitivity of DBS-fingerprick and DBS-venous was 93%, while the specificity of both DBS methods was 95%. The results demonstrated that the Abbott RealTime HIV-1 assay with DBS sample protocol is highly sensitive, specific and precise across a wide dynamic range and correlates well with