Laboratory Assays in the Clinical Management of Antiretroviral Therapy

  • Author: Mark Holodniy, MD (More Info)
  • Editors in Chief: Daniel R. Kuritzkes, MD; Joseph J. Eron, Jr., MD
  • Last Reviewed: 12/12/17 (What's New)


  • One phenotypic tropism assay using plasma virus is available
    • Results are reported as R5, X4, or R5/X4 (dual/mixed)
    • Enhanced sensitivity version of this assay in current use can detect X4-tropic virus nearly 100% of the time when X4 virus is present at 0.3% of the total viral population[Trinh 2008; Su 2008; Reeves 2007]

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Keywords: Tropism