Sensitivity analysis examining the cost of HIV counseling and testing. When the prevalence of HIV infection is > 1%, the lines reflecting cost-effectiveness ratios converge. Only at prevalences of < 0.1% do the costs of counseling and testing drive the cost-effectiveness ratio. QALY, quality-adjusted life-year. Adapted from the following article with permission from Elsevier: Walensky RP, Weinstein MC, Kimmel AD, et al. Routine human immunodeficiency virus testing: an economic evaluation of current guidelines. Am J Med 2005; 118:292–300.