Sentinel hospital surveillance of HIV infection in Quebec. Quebec Sentinel Hospital HIV-Seroprevalence Study Group

OBJECTIVE: To measure the HIV seroprevalence rate in a surrogate sample of the general population in the province of Quebec, using a network of sentinel hospitals. DESIGN: Anonymous unlinked sentinel surveillance study. SETTING: Outpatient surgery units in 19 acute care hospitals throughout Quebec. PARTICIPANTS: All patients attending the outpatient surgery units from November 1990 to October 1992. A total of 61,547 plasma samples were obtained from leftover blood samples collected for cell counts. Fifty samples were excluded because of an insufficient amount of plasma and one because of an indeterminate result. INTERVENTION: HIV antibody testing with enzyme-linked immunosorbent assay; positive results confirmed with radioimmunoprecipitation assay. OUTCOME MEASURES: HIV antibody status, sex, year of birth and area of residence. RESULTS: The crude seroprevalence rate among the subjects aged 15 years or more was 0.4 per 1000 population (95% confidence interval [CI] 0.2 to 0.7) among the women and 3.6 per 1000 population (95% CI 2.8 to 4.4) among the men (p