Evaluating the use of reactivity levels to inform risk communication and improve service user experience in an HIV self-sampling service.

Objectives: This service improvement study scoped the value of using quantitative reactivity levels (RL) to introduce a two-tier counselling approach in HIV self-sampling services. The objectives were to (1) use self-reported confirmatory test results to estimate the positive predictive value (PPV) of the first-line assay and (2) to calculate the impact on the PPV and theoretical negative predictive value of a range of proposed RL thresholds, which could be used to differentiate between higher and lower reactive results.

Methods: We studied HIV testing data from a UK-based online sexual health service from 1 December 2018 to 15 July 2020.