HIV surveillance and diagnostic testing for HIV infection share elements in
common, yet differ notably in context. Clinical testing provides vital inf
ormation for individual medical and behavioral decisions, whereas surveilla
nce, which focuses on populations, provides information to develop policy,
direct resources, and plan services. HIV/AIDS surveillance has evolved over
the course of the epidemic, reflecting changes in scientific knowledge, po
pulations affected, and information needs. Likewise, the benefits of early
diagnosis of HIV have become increasingly apparent with advances in HIV tre
atment. This article examines the changing context of HIV/AIDS surveillance
and discusses the potential impact of HIV surveillance practices and polic
ies on HIV testing behaviors. Special emphasis is placed on the importance
of protecting the confidentiality of HIV/AIDS surveillance data and on the
role of health department in monitoring the impact of surveillance policies
on test-seeking patterns and behaviors.