Which test is described as an HIV confirmatory test?

• A. RPR
• B. FTA
• C. Western Blot
• D. RIBA

Answer: (C)

In HIV testing, after a screening test flags a potential infection, a confirmatory test is used to verify the presence of antibodies to HIV’s proteins. Western blot does this by separating HIV proteins and testing the patient’s serum for antibodies that bind to those specific proteins. The result is a pattern of bands corresponding to multiple HIV components. A true HIV infection typically shows antibodies to several viral proteins, so the appearance of the expected combination of bands confirms the infection. If only one band appears or the pattern is unclear, the result is inconclusive and requires retesting or a different assay.

RPR and FTA-ABS are tests related to syphilis, not HIV, so they aren’t used to confirm HIV infection. RIBA was used as an HIV confirmatory test in the past, but Western blot has been the standard confirmatory method in many settings.