Evaluating the CDC program for HIV counseling and testing.

The Centers for Disease Control is conducting two investigations of the outcomes of HIV counselling and testing services offered persons at high risk for infection with the human immunodeficiency virus (HIV). One investigation is a trial conducted at sexually transmitted disease clinics where an enhanced version of HIV counseling and testing is compared with a standard version. The other investigation is a longitudinal study of the effects of HIV counseling and testing in drug treatment programs that use methadone therapy. In the evaluation, comparisons are being made of different ways of offering HIV counseling and testing and of the effectiveness of the program among persons who know their HIV serostatus and those who do not. The outcome variables include self-reported sexual and drug-using behaviors, together with corroborating laboratory tests, drug treatment compliance, mental health effects, and services utilization. Methodological, practical, and sociopolitical challenges were encountered in the evaluations. Possible solutions to the problems are described. The authors conclude that the designs of the evaluations were appropriate, but that considerable resources are required to carry them out. In settings with low levels of resources, thorough evaluation of the process and an assessment of the immediate outcomes may be the most appropriate evaluation strategy. As HIV counseling and testing are of fundamental importance to national and international HIV prevention efforts, their evaluation is a critical issue.