We applaud Freedberg and Samet1 for their recent contribution and suggestion that physicians lower the clinical threshold for use of human immunodeficiency virus (HIV) testing. They argue that HIV testing should be used for screening purposes rather than solely for diagnosis because testing has 2 advantages: it can help to route infected persons into effective care, and it can help people to reduce their sexual risk behavior. While we agree that these outcomes are desirable and that HIV testing is decidedly beneficial for those who learn that they are infected, we are concerned that the authors are too optimistic regarding the impact of HIV testing on sexual risk behavior.