Per current guidelines, genotypic resistance testing (sequencing of the protease and reverse transcriptase genes) should be performed in an HIV-infected person in which situation?
- A Only after two consecutive years on antiretroviral therapy regardless of viral load
- B At baseline before initiating antiretroviral therapy, and at confirmed virologic failure with viral load above roughly 1000 copies per mL ✓
- C Whenever CD4 count falls below 350 cells per microliter irrespective of treatment status
- D Only when the patient develops an opportunistic infection despite therapy
Correct answer: B. At baseline before initiating antiretroviral therapy, and at confirmed virologic failure with viral load above roughly 1000 copies per mL
Explanation
Baseline genotypic testing detects transmitted drug-resistant variants, which occur at meaningful rates even in India, and allows construction of a fully active initial regimen. Testing is also indicated at confirmed virologic failure once plasma viral load exceeds approximately 1000 copies per mL, below which amplification of the pol gene is unreliable. CD4 decline alone and opportunistic infections do not indicate resistance and are not triggers for sequencing.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.