Abstract
Introduction
The World Health Organization (WHO) HIV diagnostic strategy requires six rapid diagnostic tests (RDTs). Point-of-care nucleic acid tests (POC NATs) are costlier, less sensitive, but more specific than RDTs.
Methods
We simulated a one-time screening process in Côte d’Ivoire (CI; undiagnosed prevalence: 1.8%), comparing WHO- and CI-recommended RDT-based strategies (RDT-WHO, RDT-CI) and an alternative: POC NAT to resolve RDT discordancy (NAT-Resolve). Costs included assays (RDT: $1.47; POC NAT: $27.92); ART ($6–22/month); HIV care ($27–38/month). We modeled two sensitivity/specificity scenarios: high-performing (RDT: 99.9%/99.1%; POC NAT: 95.0%/100.0%) and low-performing (RDT: 91.1%/82.9%; POC NAT: 93.3%/99.5%). Outcomes included true/false positive/negative (TP, TN, FP, FN) results, life expectancy, costs, and incremental cost-effectiveness ratios (ICERs: $/year-of-life saved [YLS]; threshold ≤$1,720/YLS [per-capita GDP]).
Results
Model-projected impacts of misdiagnoses were: 4.4y lost (FN versus TP; range: 3.0–13.0y) and a $5,800 lifetime cost increase (FP versus TN; range: $590–$14,680). In the high-performing scenario, misdiagnoses/10,000,000 tested were lowest for NAT-Resolve versus RDT-based strategies (FN: 409 versus 413–429; FP: 14 versus 21–28). Strategies had similar life expectancy (228 months) and lifetime costs ($220/person) among all tested; ICERs were $3,450/YLS (RDT-CI versus RDT-WHO) and $120,910/YLS (NAT-Resolve versus RDT-CI). In the low-performing scenario, misdiagnoses were higher (FN: 22,845–30,357; FP: 83,724–112,702) and NAT-Resolve was cost-saving.
Conclusions
We projected substantial clinical and economic impacts of misdiagnoses. Using POC NAT to resolve RDT discordancy generated the fewest misdiagnoses, was not cost-effective in high-performing scenarios, but may be an important adjunct to existing RDT-based strategies in low-performing scenarios.
Nitrocellulose-bound achromopeptidase for point-of-care nucleic acid tests