Methods: We examined the cost differences between home-based and clinic-based testing and the cost-effectiveness of home testing for chlamydia and gonorrhea in high risk young women based on the DAISY study, a randomized controlled trial which showed increased test frequency with home testing and no differences in sexually transmitted disease (STD) detection between groups. Direct and indirect costs were estimated for home and clinic testing, and cost-effectiveness was calculated as the cost per additional test performed per patient. One-way and probabilistic sensitivity analyses were performed.

Results: Cost questionnaire and testing frequency results were available for 388 subjects (197 home testing, 191 clinic testing). In the clinic testing group, direct costs were estimated as $49/test and indirect costs (the costs of seeking or receiving care) as $62/test. Home testing direct costs were $25/test. When considering all tests (whether asymptomatic or not), home testing was cost saving because fewer clinic-based tests were performed, offsetting the costs of increased home testing. Cost savings were not seen when only asymptomatic tests or when recruitment subgroups were considered, with costs ranging from $2.16-$24.50 per additional test performed per patient, since increased home testing costs were not offset by decreases in clinic-based testing. Home testing is cost saving if clinic testing rates decrease by more than 22.5% of the increase seen in home testing rates due to program adoption. Results were also sensitive to variation of home testing costs, clinic direct costs, and time spent seeking or receiving care. In probabilistic sensitivity analyses when equal STD detection is assumed with either program (as seen in the trial), home testing is cost saving in 52% of model iterations when all testing is considered; if only asymptomatic testing is considered, home testing saves costs in 22% of model iterations.

Conclusions: A program encouraging home STD testing increases overall testing rates and could be cost-saving when direct and indirect costs of care are considered. If no additional STD detection occurs as a result of home testing programs, cost reductions depend on whether changes in clinic testing frequency occur.