Feasibility and reliability of decentralized HIV-1 viral load monitoring on self-sampled blood.

Abstract

Home-based blood self-sampling for HIV-1 viral load (VL) monitoring has the potential to alleviate pressure on healthcare systems by reducing clinic visits for people with HIV. This study evaluates the feasibility and reliability of HIV-RNA measurements in self-sampled blood and in viremic samples. Between September 2024 and March 2025 participants were recruited at the outpatient clinic. Self-sampled blood was collected using the TassoPlus device at home and compared to conventional HIV-RNA testing from the same individual. Only samples containing a minimum volume of 200 μL plasma were deemed eligible for analysis. Also, 30 stored viremic samples (HIV-1 RNA 100-950 copies/mL) aliquoted into 200 μL volumes were included and compared to conventional HIV-RNA testing. The Alinity m HIV-1 assay (Abbott), validated for low plasma volumes, was used for all samples. Agreement was assessed using Pearson correlation and Bland-Altman analysis. Sample quality was assessed based on plasma volume and clotting. User-friendliness of the TassoPlus was evaluated through a questionnaire. Of the 62 participants (median age 56 [46-66]; 81% male), 63% (n = 38) returned the sample, yielding a mean plasma volume of 207 μL (range:10-550). Of these, 18 samples (29%) were excluded due to insufficient volume for analysis. HIV-RNA in both self-sampled and stored samples (n = 50), correlated with conventional samples (r = 0.800). However, in four low-volume viremic samples, HIV-RNA was <100 copies/mL, while conventional sampling detected 148, 260, 501 and 759 copies/mL, respectively. Bland-Altman analysis showed a mean difference of 0.08 log copies/mL (95%LOA:-0.79-0.95) between conventional sampled blood and low-volume samples (self-sampled/stored samples). No clotting was observed. Furthermore, 57% of participants expressed interest in using the TassoPlus, and 48% rated its usability as easy or very easy. Self-sampling with TassoPlus presents challenges, including high rates of unsuccessful sampling and potential failure to detect low-level viremia. Therefore, significant refinements are essential for reliable clinical use.