Setting standards for the Wisconsin HIV Counseling and Testing Program: an application of threshold analysis.

Human immunodeficiency virus (HIV) counseling and testing (CT) services are an important component of any comprehensive HIV prevention program. Because resources are limited and must be used wisely, it is important to determine if the expenditures on CT services are sufficiently effective that they might be considered cost-saving or cost-effective to society. The policy analysis technique of "threshold analysis" was employed to determine how many HIV infections the publicly funded Wisconsin CT program would have to prevent in order to be considered cost-saving or cost-effective. Depending on the calculation method used, the threshold for the minimum number of HIV infections that must be averted ranges between approximately 1 and 18 (for the year 1994). Although the exact number of HIV infections prevented by these services in Wisconsin in unknown, the best estimate of this number is well over the required threshold. Hence, HIV CT services in the state of Wisconsin appear to be cost-saving to society.