2067. Missed Opportunities for Confirmatory HIV Testing at a Midwestern Medical Center

Abstract

Background The currently recommended HIV testing algorithm begins with a 4th generation antigen/antibody (Ag/Ab) combination immunoassay, which allows for early detection of HIV. However, this assay’s high sensitivity can result in false positives that must be distinguished from acute infections via an HIV nucleic acid test (NAT). At our medical center, HIV NATs are recommended in the lab report for anyone with a positive p24Ag component on the screening assay, but they are not done reflexively by the lab as it requires a different blood tube. Thus, difficulties arise in obtaining the NAT, such as providers failing to order the test or patients failing to return for another blood draw, jeopardizing the diagnosis of early HIV. Methods We conducted a retrospective chart review of adult patients at a Midwest academic medical center with a positive p24Ag on the HIV-1/2 Ag/Ab combination assay between Jan. 1, 2017 and Feb. 21, 2021. We assessed if appropriate confirmatory testing was performed, identified barriers to missed opportunities for confirmatory testing, and used t-tests and Fisher’s exact tests to evaluate differences between those who did and did not receive confirmatory testing. Results Of 37 people with a positive p24Ag on the HIV Ag/Ab immunoassay, 6 (17%) did not have an HIV NAT performed within 30 days of their positive screening test. Of these 6 cases, the ordering provider did not acknowledge the need for a confirmatory test in 3 cases, the patient did not return for the test in 1 case, and other factors prevented follow-up in 2 cases. Of those who had an HIV NAT ordered, 7 (23%) had a positive HIV NAT. Younger age was significantly associated with completion of appropriate confirmatory testing (p=0.05), but other factors including sex, race, insurance status, having a primary care provider, specialty of ordering provider, encounter location, and test indication were not. Conclusion Our review identified multiple missed opportunities for confirmatory HIV testing following a positive p24Ag component on the HIV screening test. Provider lack of knowledge/awareness of the need for appropriate testing was the most common barrier. A quality improvement initiative will be undertaken to minimize future risk of missed opportunities for confirmatory testing. Disclosures Paul D. Fey, PhD, BioFire: Advisor/Consultant|BioFire: Grant/Research Support|Merck: Grant/Research Support Sara H. Bares, MD, Gilead Sciences: Expert Testimony|GSK ViiV Healthcare: Grant/Research Support|Janssen: Grant/Research Support.