1782. Real-World HIV Diagnostic Testing Patterns in the United States

Background Current HIV diagnostic laboratory testing guidelines from the US Centers for Disease Control and Prevention (CDC) recommend a sequence of tests for detection, differentiation, and confirmation of HIV-1 and HIV-2 diagnosis. There is a gap in knowledge about real-world implementation of the testing algorithm. The aim of this study was to characterize the population that underwent HIV antibody differentiation and confirmatory testing and to describe subsequent testing patterns from a large US clinical laboratory database. Methods Patients who received one or more HIV-1/2 antibody differentiation test (BioRad Geenius™ HIV 1/2 Supplemental Assay [Geenius]) in the Quest Diagnostics laboratory database between January 1, 2017 and December 31, 2017 were selected into the study; earliest test date was index date. Geenius tests, HIV-1 qualitative RNA (Aptima HIV-1 RNA Qualitative Assay [Aptima]), and HIV-2 DNA/RNA confirmatory tests subsequent to index date were captured. Study measures included pt demographic characteristics, testing frequency and sequencing, and test results. For patients with >1 Geenius test in 2017, concordance between index and subsequent test results was assessed. Results There were 26,319 unique patients identified who received ≥1 HIV antibody differentiation result from the Geenius assay. Mean age was 40.7 ± 14.3 years, 66.4% were male, and 42.5% were from southern states. Among the study population, there were 28,954 Geenius, 7,234 Aptima, and 298 HIV-2 DNA/RNA confirmatory tests. 26.4% of Geenius test results were discordant with the initial positive fourth-generation HIV screening results and required subsequent confirmatory testing. In terms of sequencing, the CDC-recommended HIV diagnostic algorithm was followed 74% of the time after screening. 8.5% of patients had >1 Geenius test in 2017; 11.2% of the retests returned different results compared with the first test. Conclusion The CDC recommended algorithm for HIV diagnosis is complex for laboratories to implement and currently available assays do not support testing efficiency. To mitigate observed inefficiencies and reduce the laboratory burden of HIV testing, a more accurate and reliable approach for HIV differentiation and confirmatory testing is needed. Disclosures All authors: No reported disclosures.