Which laboratory test is commonly used to confirm a diagnosis of HIV infection?

• A. Gram stain
• B. Catalase test
• C. Western blot assay
• D. Coagulase test

Answer: (C)

Verified step by step guidance

1. Understand that the question asks for the laboratory test commonly used to confirm a diagnosis of HIV infection, which involves detecting specific antibodies or viral proteins.
2. Recall that Gram stain is a technique used to classify bacteria based on their cell wall properties and is not used for viral infections like HIV.
3. Recognize that the Catalase test and Coagulase test are biochemical tests used to identify bacterial species, particularly Staphylococcus and Streptococcus, and are not relevant for HIV diagnosis.
4. Know that the Western blot assay is a serological test that detects antibodies specific to HIV proteins, making it a confirmatory test after initial screening.
5. Conclude that the Western blot assay is the confirmatory laboratory test for HIV infection because it provides specific evidence of HIV antibodies, confirming the diagnosis.