Researchers recruited adults without known HIV disease who attended a large, urban emergency department. None of the patients had indicators of urgent life-threatening or severe emergencies. Researchers collected oral samples from the patients and sent the samples to the emergency department laboratory. The tests were read within 20 to 40 minutes. If results were negative, patients received no further testing for HIV. If results were reactive (positive), patients had multiple blood tests to confirm HIV infection. These tests included a serum enzyme-linked immunoassay, a single serum Western blot test, CD4 count, and plasma HIV-1 RNA measurement. Results of the confirmatory tests were not available the day of the emergency department visit. The researchers then examined the number of patients who had both reactive results and confirmed HIV infection.