Real-World Positive Predictive Value and False Positive Rates of Laboratory-Based HIV Antigen/Antibody Testing by Age...

The Centers for Disease Control and Prevention (CDC) recommends testing for HIV using a laboratory-based HIV antigen/antibody (Ag/Ab) test with confirmatory testing for reactive results. However, the positive predictive value (PPV) of screening may vary across populations with differing HIV prevalence. We evaluated age- and sex-specific false positive rates (FPRs) and PPV of HIV Ag/Ab tests in a large real-world national laboratory data set.

Data from the Quest Diagnostics national HIV laboratory database from January 2019 through June 2024 were analyzed. Excluding persons with prevalent HIV infection, we examined the completed CDC diagnostic algorithm results to assess performance of HIV Ag/Ab screening tests. FPR and PPV of the Ag/Ab test were estimated by year, sex, age, and census region.

Among 21.9 million HIV Ag/Ab tests, the overall FPR was 0.14% [95% confidence interval (CI): 0.14 to 0.14], with higher FPRs among older adults (0.22% for aged 65-74 years and 0.27% for ≥75 years). The overall PPV was 68.4% (95% CI: 68.1 to 68.7). PPV was lowest among adolescents, at 26.7% (95% CI: 19.1 to 34.3) for those aged 13-14 years and 31.9% (95% CI: 29.1 to 34.6) for those aged 15-17 years. Low PPVs were also observed among women of childbearing age (15-44 years) and persons aged ≥75 years.

Real-world PPV of HIV Ag/Ab testing varies substantially across age and sex groups, suggesting that the opt-out routine screening strategy may be less efficient among young adolescents aged 13-14 years and persons aged ≥75 years. CDC recommends HIV testing when clinical suspicion or individual risk is present.