HIV-1 genotyping detects HIV genomic mutations that confer resistance to specific types of antiretroviral drugs. Current sequence-based assays detect resistance mutations in the protease (PR) and part of the reverse transcriptase (RT) genes. Two Food and Drug Administration (FDA)-approved genotyping methods are commercially available: the ViroSeq HIV-1 genotyping system, version 2.0 (Celera Diagnostics) and the Trugene HIV-1 genotyping system for drug resistance (Siemens Healthcare Diagnostics).
Use
As an aid in monitoring and treating HIV-1 " “infected individuals:
At initial presentation, before initial drug therapy
At drug therapy failure
Limitations
Viral load not <1,000 copies/mL for TrueGene and 2,000 copies/mL for ViroSeq.
The FDA-approved tests are specific for analysis of subtype B HIV-1 only. For analysis of non " “B HIV-1 strains that represent up to 90% of HIV-1 variants circulating worldwide, lab-developed tests should be used.