What is the definitive method for diagnosing human immunodeficiency virus (HIV) infection?

The definitive method for diagnosing human immunodeficiency virus (HIV) infection involves performing a positive enzyme-linked immunosorbent assay (ELISA) followed by confirmation with Western blot tests. The ELISA test is sensitive and can detect antibodies to HIV in the blood, making it a suitable first-line screening tool. When the ELISA test result is positive, it must be confirmed with the Western blot test, which is considered more specific and provides a definitive diagnosis. This two-step process ensures both sensitivity and specificity in diagnosing HIV infection.

High-risk sexual behaviors, extreme weight loss, high fever, and the presence of opportunistic infections can be indicative of HIV infection or its stages, but they are not definitive methods of diagnosis. Instead, they can suggest the possibility of HIV, emphasizing the importance of conducting proper laboratory tests for conclusive evidence.