FFTRP - Clinical: Trofile Co-Receptor Tropism Assay

Test Catalog

Test Name

Test ID: FFTRP    
Trofile 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 a patient's HIV-1 viral load is > or = 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

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



Co-receptor tropism could not be determined by the Trofile assay. Common causes of a non-reportable result are viral load <1,000 copies/mL, reduced viral fitness, or compromised sample collection/handling.