Performance of patient-collected dried blood spot specimens for HIV-1 viral load testing: evidence from the DO ART Study in South Africa

• Published in: AIDS (London)
• Main Authors: Sahu, Maitreyi, Schaafsma, Torin, Szpiro, Adam A., Van Rooyen, Heidi, Asiimwe, Stephen, Shahmanesh, Maryam, Krows, Meighan L., Sithole, Nsika, Van Heerden, Alastair, Barnabas, Ruanne V.
• Format: Journal Article
• Language: English
• Published: 13.09.2024
• ISSN: 0269-9370; 1473-5571; 1473-5571
• DOI: 10.1097/QAD.0000000000004011

Objective: Evaluate the clinical utility of patient-collected dried blood spots (DBS) in measuring HIV-1 viral load (VL) for monitoring antiretroviral therapy (ART) compared to provider-collected DBS and blood plasma. Design: In a randomized trial of community-based delivery of ART in South Africa, we assessed performance of: (1) DBS specimens compared to plasma, and (2) participant-collected versus staff-collected DBS specimens, to measure HIV-1 VL. Methods: The bioMérieux NucliSENS EasyQ HIV-1 v2.0 assay was used for VL measurement. From October 2017 to November 2019, we collected 996 pairs of plasma/DBS specimens from 760 participants and 315 pairs of staff-/participant-collected DBS cards from 261 participants. We assessed DBS test sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) using the WHO failure threshold of 1000 copies/mL. Log-transformed VL was compared using concordance correlation coefficients (CCC) and mean differences from linear mixed models. Results: In a population with 13% detectable VL, DBS VL compared with plasma VL had 91% (95% CI: 86–95) sensitivity, 99% (98–100) specificity, 94% (90–98) PPV, and 99% (98–99) NPV. We observed high agreement between staff-collected DBS VL and plasma VL (CCC: 0.94), and between participant-collected DBS VL and plasma VL (CCC: 0.92). Correlation between participant- and staff-collected DBS was very high (CCC: 0.97; mean difference for those with a detectable result: -0.10 log 10 copies/mL [-0.21–0.02]). Conclusions: VL results from participant-collected DBS are clinically comparable with those collected by clinical staff and using blood plasma. Self-collected DBS has potential for use for ART monitoring outside the clinic.