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HIV-1 Genotypic Testing

Genotypic testing isolates amino acid sequences of viral proteins and analyzes for the presence of mutations associated with antiretroviral (ARV) resistance. A rules-based algorithm is utilized to make predictions of ARV susceptibility based on the presence of mutations in the patient viral population.
Provider and patient standing in exam room talking over a chart

The Department of Health and Human Services (DHHS) guidelines

The DHHS guidelines recommend genotypic testing at baseline and at first and second treatment failures in patients with suboptimal response or virologic failure.1

Labcorp offers several genotypic testing options for a combination of HIV-1 ARV classes, as well as targeted testing for integrase inhibitors.

Genotypic testing provides a three tiered assessment of drug susceptibility:

  • Sensitive

  • Resistance possible

  • Resistant

scientist holding sample up to the light

Genotypic testing options
 

551700

GenoSure PRIme®

Drug classes tested: NRTIs, NNRTIs, INIs, PIs

View Test Specifications

551697

GenoSure® MG

Drug classes tested: NRTIs, NNRTIs, PIs

View Test Specifications

551871

GenoSure® Integrase

Drug classes tested: INIs

View Test Specifications

551776

GenoSure Archive®

Drug classes tested: NRTIs, NNRTIs, INIs, PIs

View Test Specifications

All genotypic assays require a viral load of > 500 copies/mL with the exception of GenoSure Archive®, which was designed for use in patients with non-detectable viral loads or low level viremia. 

If genotypic testing fails on the initial attempt to result, the laboratory will perform in-house viral load testing to confirm adequate viral material. If the viral load is < 500 copies/mL, the viral load will be reported and the client will be billed for viral load testing. 

If a patient’s viral load varies around the 500 copies/mL viral load requirement, it is possible to order viral load reflex testing (550920) in which a viral load reflexes to either GenoSure PRIme® or GenoSure Archive®. 

  • If the viral load is > 500 copies/mL, testing will reflex to GenoSure PRIme®
  • If the viral load is < 500 copies/mL, testing will reflex to GenoSure Archive®

Viral load reflex testing is also available for GenoSure® MG and GenoSure PRIme®.

Reference

  1. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV. Department of Health and Human Services. Available at https://clinicalinfo.hiv.gov/sites/default/files/guidelines/archive/AdultandAdolescentGL_2021_08_16.pdf. Accessed June 26, 2023