FFTRO - Clinical: Trofile DNA Co-Receptor Tropism Assay

Test Catalog

Test Name

Test ID: FFTRO    
Trofile DNA Co-Receptor Tropism Assay

Useful For Suggests clinical disorders or settings where the test may be helpful

To determine the co-receptor tropism (CCR5, CXCR4, or dual/mixed) of a patient's HIV-1 strain for selection of CCR5 co-receptor antagonist therapy, when patient's HIV-1 viral load is <1,000 copies/mL.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


Interpretation Provides information to assist in interpretation of the test results

Trofile DNA Viral Classification


CCR5 Tropic (R5) HIV-1:

Virus uses CCR5 to enter CD4+ cells.


CXCR4 Tropic (X4) HIV-1:

Virus uses CXCR4 to enter CD4+ cells.


DUAL /MIXED Tropic (D/M) HIV-1:

Dual-tropic viruses can use either CXCR4 or CCR5 to enter CD4+ cells.  Mixed-tropic populations contain viruses with 2 or more tropisms.



Co-receptor tropism could not be determined.  Common causes of nonreportable results are reduced viral fitness or compromised sample handling.  Please note that Trofile DNA sample collection and handling instructions differ from Trofile and other Monogram assays.


Trofile uses the complete gp160 coding region of the HIV-1 envelope protein ensuring that all of the determinants of tropism are tested. Subtype is determined based on the HIV-1 gp41 envelope region.