At-Home Point-of-Care Urine Tenofovir Testing for Adherence Monitoring: Feasibility and Comparison with Adherence Metrics in Dried Blood Spots.

BACKGROUND

Scalable, low-cost strategies for monitoring antiretroviral therapy adherence are increasingly important, particularly in decentralized and telehealth-based care settings. This study assessed both the feasibility and performance of at-home, point-of-care (POC) urine tenofovir (TFV) testing for adherence monitoring, using tenofovir diphosphate (TFV-DP) levels in dried blood spots (DBS) as a pharmacological standard of adherence.

SETTING

This study was conducted within the LetSync cohort of people with HIV in primary romantic relationships, primarily Black men who have sex with men, across the U.S.

METHODS

Participants self-collected POC urine TFV testing and DBS samples over five timepoints across eight months. Adequate adherence was defined as TFV-DP ≥4 doses/week in DBS. Generalized estimating equation models evaluated associations between urine TFV results and DBS-based adherence, as well as the probability of sample return over time.

RESULTS

Among 86 participants and 341 paired samples, detectable urine TFV was strongly associated with adequate adherence in DBS (aRR = 2.86; 95% CI: 1.37-5.99). The urine POC test demonstrated high sensitivity (97%) and positive predictive value (85%), with lower specificity (31%). Across timepoints, urine samples showed higher return rates compared to DBS (aRR = 1.04; 95% CI: 1.01-1.08). Participants with detectable viral load had lower return rates for DBS compared to urine.

CONCLUSIONS

At-home POC urine TFV testing is a sensitive and feasible approach for monitoring adherence. Its simplicity and consistently high return rates support its potential as a practical adherence monitoring tool, particularly in settings where VL testing is infrequent or logistically limited.