title: Trofile HIV co-receptor usage assay.
abstract: BACKGROUND
  The introduction of CCR5 antagonists increases the options available for constructing therapeutic drug regimens for HIV-positive patients. However, as these drugs do not inhibit HIV variants that use the CXCR4 co-receptor, a pretreatment test is required to determine accurately HIV co-receptor usage (tropism) before initiating CCR5 antagonist-based therapy.
  
  
  OBJECTIVE
  To discuss the Monogram Trofile assay as a diagnostic tool for determining HIV tropism by critically reviewing reported literature and available data.
  
  
  CONCLUSIONS
  Monogram Trofile has become, largely by default, the de facto standard for HIV tropism assay. However, there is significant room for improvement in the speed, cost and availability of the test. Furthermore, the test is not quantitative, requires high-input HIV RNA viral loads, and produces results that are less biologically stable than expected. These technical considerations may limit the use of CCR5 antagonists in therapy. Nevertheless, this test is likely to remain the most widely used tropism diagnostic for the short term. We expect that a more practical and possibly more accurate method for measuring HIV tropism can be developed.
authors.affiliation: 20/48 Nelson Street, Annandale, NSW 2038, Australia +0 450 010 207 ; +0 604 806 9044 andrewjohnlow@gmail.com.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Low
authors.forename: Rachel A
authors.initials: RA
authors.lastname: McGovern
authors.forename: P Richard
authors.initials: PR
authors.lastname: Harrigan