Final answer:
Retesting for HIV after three months ensures accurate detection of antibodies, minimizing the risk of false negatives due to the seroconversion window, and confirmatory tests like Western blot or PCR ensure a precise diagnosis.
Step-by-step explanation:
It is recommended to retest for HIV after three months because it may take up to 3 months following an initial infection for the immune system to produce antibodies at levels detectable by tests. An early test might return a false-negative result due to the seroconversion window, the period during which antibodies have not yet reached the detection threshold. Confirmatory tests like Western blot or PCR are used after a positive initial test to rule out false positives and accurately diagnose HIV infection.