True and false positives in HIV screening tests in three Peruvian algorithms, 2023

Abstract

There are few countries that evaluate the performance of their algorithms. Objective. Determine the proportion of true and false positives to HIV screening tests in three Peruvian algorithms, 2023. Methods. We compared the serological results of screening and confirmation of the conventional, new and a latest algorithm recommended by the WHO. Results. 4030 patients were studied; conventional algorithm, of 3027 people reactive to a screening test, 88.3% (2742/3027) were positive to the confirmatory serological test (true positives), corresponding to 11.7% (355/3027) false positives. New algorithm, of 951 people reactive to two screening tests, 92.6% (881/951) were true positives and 7.4% (70/951) false positives; The last algorithm did not present false positives (0/52) to three reactive screening tests. Conclusion. The conventional and new algorithms are reliable, but serological confirmation should be considered in the new algorithm when the Viral Load is undetectable; We recommend that where confirmatory testing is not available, samples be processed using three different methodologies.