HIV Antibody Screening (1992)
RECOMMENDATIONS
- Obtaining a history of sexual behaviour and injection drug use and offering counselling has limited sensitivity for identifying HIV-positive people in the general population, but its inclusion is likely to increase detection of risk behaviours. Its inclusion in the periodic health examination of asymptomatic people in the general population is based on expert opinion.
- Recommendations for HIV antibody screening must consider characteristics of the screening manoeuvre, particularly sensitivity and specificity, and the availability of treatment for asymptomatic seropositive people. There is insufficient evidence to recommend the inclusion or exclusion of HIV antibody screening among pregnant women. Because the prevalence of HIV infection is lower in Canada than in the United States the generalizability of the U.S. studies is questionable. Even with excellent test characteristics the positive predictive value cannot be perfect with a low prevalence rate. Screening should be considered for those in large cities because of the low sensitivity of targeted screening and better compliance with routine screening.
- HIV antibody screening should be offered to people with high-risk behaviours or those in high-risk groups because of good evidence of the effectiveness of early treatment in delaying the development of AIDS and the efficacy of aerosol pentamidine prophylaxis. However, labelling is a problem and there is no information about the long term effects of treatment.
- Other interventions that might be offered to those found to have HIV infection include prolonged treatment for specific secondary infections and changes in vaccination schedules. In addition, cohort studies suggest that testing followed by counselling may reduce the spread of HIV infection among injection drug users and homosexual men.
- There is fair evidence to recommend HIV antibody screening for neonates of HIV-positive women; however; antibody screening is not specific or sensitive, and diagnostic tests, such as the viral DMA polymerase chain reaction or virus isolation, must be done. Follow-up and vaccinations will be different for seropositive children.
- There is insufficient evidence to recommend the inclusion or exclusion of HIV antibody screening in low-risk populations. The harm caused by false-positives results is balances by any treatment benefits gained by the few seropositive people identified.