['In September 2006, the Centers for Disease Control and Prevention (CDC) recommended routine (nontargeted) human immunodeficiency virus (HIV) screening for all patients in the emergency department (ED). Although the American College of Emergency Physicians has endorsed these recommendations, the College expressed concern that that their adoption may lead to an increase in the length of stay (LOS) for ED patients. This study therefore analyzed the effect of nontargeted HIV screening on LOS in a cohort of ED patients.', 'The analysis was performed in an urban, Level I trauma center that offers nontargeted opt-out HIV screening using dedicated HIV screeners. The LOS of all discharged patients who accepted HIV screening between May 2008 and December 2009 were compared with those of a cohort of patients over the same time period who were offered an ED HIV screening test but declined or were found to be not eligible. Median LOS was compared using the Wilcoxon rank sum test, and a multivariable linear model was used to assess the relationship between the acceptance of HIV testing and ED LOS.', 'Over the 20-month study period, there were 18,577 records of discharged patients who were offered an HIV screening test and for whom there were data about LOS. Of these, 10,286 patients accepted HIV screening, and 8,291 patients declined or were found not to be eligible. Individuals who accepted the HIV test had an LOS that was 2% longer compared to those who did not accept the test (regression beta coefficient = 1.02, 95% confidence interval [CI] = 1.00 to 1.03, p = 0.04).'] Does nontargeted rapid human immunodeficiency virus screening provided by dedicated personnel adversely affect emergency department length of stay?