The diagnosis of human immunodeficiency virus infection in technology-rich countries is accomplished by detection of anti-human immunodeficiency virus in serum with almost 100% sensitivity and specificity. The use of laboratory-based markers for monitoring disease prognosis and therapeutic efficacy is becoming highly sophisticated. Published and continuing studies demonstrate the validity of using various markers as well as the correlation between markers as indices of clinical prognosis and progress and outcome. Used quantitatively, markers may be used to monitor therapy. Exciting prospects for assessing an individual's antiviral resistance and tailoring therapy are on the horizon. However, diagnostic tests and tests for prognosis and management remain unavailable to many human immunodeficiency virus-infected people.