How is drug resistance testing used in HIV care?

• A. Determines viral load.
• B. Genotype resistance testing guides selection of ART regimens by identifying mutations associated with resistance to NNRTIs, NRTIs, PIs, or integrase inhibitors.
• C. Predicts side effects of medications.
• D. Only helps diagnose HIV infection.

Answer: (B)

Drug resistance testing in HIV care looks for mutations in the virus that confer resistance to antiretroviral drugs. Genotype resistance testing analyzes the HIV pol gene to identify mutations linked to resistance to NNRTIs, NRTIs, protease inhibitors, and integrase inhibitors. By knowing which drugs the virus remains susceptible to, clinicians can tailor the ART regimen to maximize effectiveness and avoid drugs likely to fail due to resistance. This testing is especially useful when starting therapy in the presence of possible transmitted resistance or during virologic failure to adjust the regimen. It isn’t used to measure viral load, diagnose infection, or predict side effects.