Emergency departments (EDs) are highly valued settings for HIV screening. Most large-volume ED HIV screening programs have attenuated operational barriers by screening only ED patients who already have a blood sample available for other clinical reasons. Our objective was to estimate the proportion of HIV positive patients who are missed when an ED excludes patients for whom HIV screening would be the only indication to obtain a blood sample.

This cross-sectional analysis used existing electronic records of patients seen between 2017 and 2019 by an urban, academic ED and its HIV screening program, which includes patients regardless of whether they receive other ED blood testing. The primary outcome was the proportion of patients tested by the screening program who were newly diagnosed with HIV (Sample 1) for whom HIV screening would be the only indication for venipuncture. We secondarily 1) estimate the proportion of ED patients who received venipuncture using a representative sample of consecutively approached participants which prospectively recorded whether patients had blood obtained or intravenous catheter placement during usual ED care (Sample 2) and 2) report patient characteristics including HIV risk factors for those with and without ED venipuncture for both groups.

Of 41 persons newly diagnosed with HIV by the ED screening program (Sample 1), 13 (31.7%, 95%CI 18.6–48.2) did not undergo venipuncture for any reason other than their HIV test. The proportion of ED visits without a venipuncture (Sample 2) was 44.2% (95% CI 41.9–46.6). Patient characteristics were similar for both groups.

Screening only those patients with a blood sample already available or easily obtainable due to usual ED care, misses many opportunities for earlier HIV diagnosis. Innovation in research, policy, and practice is needed to overcome still unaddressed barriers to ED HIV screening when HIV screening is the only indication for collection of a biological sample.