BACKGROUND: Recognizing recently infected HIV cases is crucial to linking patients to care early and to prevent further transmission. In Utah, HIV viral load (VL) and CD4 tests have been reportable regardless of positivity since 2013, however, in 2015, negative results for HIV serologic tests were also mandated from entities reporting electronically. Negative results are automatically appended to existing cases, however, if no case exists, the results are stored in the Electronic Messaging Staging Area (EMSA) with identifiers for 18 months. During those 18 months, if a positive result creates a case, either manually or via ELR, any negative results in EMSA are automatically appended to the case providing a history of testing. We assessed how this system has enhanced our ability to detect recent HIV infections.
METHODS: Electronic laboratory reporting (ELR) was implemented in Utah during 2013 and accounts for roughly 85% of all reported HIV laboratory results during 2016. ELR data from January 2013 to December 2016 were exported and restricted to only include cases where a positive result found one or more previous negative results in the EMSA and appended them to the new case report. The dataset was analyzed for duplicate results and persons newly identified with HIV. Cases were reviewed to identify possible recent infections.
RESULTS: The analysis found 47 positive laboratory cases that had previous negative test results. After deduplication, 27 unique individuals were identified. Of these 27 persons, 19 (70.4%) had a previous negative result reported electronically indicating possible recent seroconversion, whereas the remaining 8 cases (29.6%) were identified as not being HIV-infected (3 cases), results mistakenly reported from another state (2 cases), being the same sample (2 cases), and having insufficient information (1 case). Further analysis of the 19 possible seroconverters found that 9 cases (47.4%) were not recently infected due to various reasons such as being previously positive but never reported. The remaining 10 cases (52.6%) had a previous Ag/Ab negative screening result followed by a positive test at least 14 days apart. Of those 10 cases, only 4 cases (40%) had the last negative and first positive tests within 180 days of each other, followed by an additional 3 cases (30%) within 365 days of each other.
CONCLUSIONS: Collecting negative laboratory data has increased the ability of HIV surveillance to ascertain recently infected cases of HIV disease. Identifying these cases will be important to focus the efforts in screening and linkage-to-care programs.