ED Screening Using Antigen-Antibody Tests Identify Previously Undiagnosed HIV

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A study found that nontargeted screening using antigen-antibody tests identified previously undiagnosed HIV infection at a rate that exceeded the CDC screening threshold by severalfold.

According to the results of a study published in the Annals of Emergency Medicine, emergency department screening for HIV with HIV antigen-antibody tests revealed new diagnoses in 0.4% of participants, and 14.5% of those infections were in the acute phase.

In this retrospective study of 9 emergency departments with HIV screening programs, researchers evaluated the results of HIV antigen-antibody testing in 214,524 unique patients. Patients with new HIV diagnoses were classified as having acute HIV infection (repeatedly positive antigen-antibody result with negative HIV-1/HIV-2 antibody differentiation assay or Western blot result) or established HIV infection (repeatedly positive antigen-antibody result with positive HIV-1/HIV-2 antibody differentiation assay or Western blot result).

A total of 839 patients (0.4%) were newly diagnosed with HIV. Of the new HIV diagnoses, 14.5% were considered acute infections, and 85.5% were considered established infections. According to the study investigators, the undiagnosed HIV infection rates “exceed the CDC [Centers for Disease Control and Prevention] screening threshold by severalfold.”

Patients with acute HIV infections tended to be younger than patients with established HIV infections and had higher median viral RNA (1,176,913 vs 50,464) and median CD4 T cell counts (349 vs 213). Furthermore, patients with acute HIV infections were more likely to have the reason for their emergency department visit classified as viral syndrome (41.8% vs 6.5%) or fever (14.3% vs 3.4%) and less likely to present for acute trauma (1.0% vs 6.1%) or musculoskeletal reasons (1.0% vs 5.5%) compared with patients with established HIV infections.

More patients with acute HIV infections were linked to care within 30 days compared with established HIV infections (55.1% vs 33.9%). In a similar fashion, patients with acute infections had a higher rate of antiretroviral treatment within 30 days (41.8% vs 20.9%).

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The investigators concluded that “nontargeted HIV screening bolstered with an additional focus on testing patients with symptoms possibly related to HIV seroconversion, such as viral syndrome, is the best strategy to identify patients with previously undiagnosed HIV infection, including those who are acutely infected.”


White DAE, Giordano TP, Pasalar S, et al. Acute HIV discovered during routine HIV screening with HIV antigen-antibody combination tests in 9 US emergency departments [published online January 8, 2018]. Ann Emerg Med. doi:10.1016/j.annemergmed.2017.11.027