Purpose: Many US sexually transmitted disease (STD) clinics conduct routine enzyme immunoassay (EIA) laboratory HIV testing that requires follow up to receive results. On-site rapid HIV testing delivers results in 20 minutes at a higher initial cost, but reduces follow up costs and risks of loss to follow up for newly identified HIV cases.
Methods: Using micro-costing techniques, we determined the average cost per person offered a rapid HIV test for two strategies: 1) rapid test with information only and 2) rapid test with risk-reduction counseling. Data were from seven public health STD clinics participating in a randomized trial comparing the effectiveness and cost-effectiveness of the two strategies. Data included staff activity logs, clinic overhead including additional space for on-site rapid testing, and supplies. We applied national labor rates and supply costs. Analysis was from the STD clinic perspective; start-up costs and patient costs were excluded. We calculated the threshold follow up cost saved per newly detected HIV case (including the cost to inform HIV-uninfected patients who return for their results) that would offset the incremental cost of on-site rapid testing. We varied the prevalence of undetected HIV infection between 0.1% and 1.0%.
Results: Offering rapid HIV testing with information costs $19/patient ($7 labor/overhead, $11 materials, $1 quality assurance (QA)/supervision) and offering rapid HIV testing with counseling costs $49/patient ($29 labor/overhead, $13 materials, $7 QA/supervision). Assuming $5/patient cost for EIA testing, the threshold follow-up cost savings to achieve budget neutrality is $13-$131 per newly detected HIV case for rapid testing with information, and $37-$375 for rapid testing with counseling (see figure).
Conclusion: Assuming a cost of $34/hour for a disease intervention specialist (DIS) for HIV test follow-up, budget neutrality requires a savings of 0.4-11.0 DIS hours per newly detected case depending on testing strategy and HIV prevalence. This does not include the public health benefits of avoiding loss to follow up and patient benefits of providing same day results. Public STD clinics may be able to implement rapid HIV testing within their current budgets, excluding start-up costs. 
See more of: The 33rd Annual Meeting of the Society for Medical Decision Making