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HelpMayo Test ID FFTRO Trofile DNA Co-Receptor Tropism Assay
Reporting Name
Trofile DNA Phenotypic Corecept TroUseful For
Detect HIV-1 coreceptor tropism; determine eligibility for CCR5 antagonist therapy such as Selzentryâ„¢ (maraviroc).
Performing Laboratory
Monogram Biosciences, IncSpecimen Type
Whole Blood EDTASpecimen Required
Specimen Type: Whole Blood
Container/Tube: Lavender-top (EDTA)
Specimen Volume: 4 mL
Collection Instructions: Draw 4 mL blood in a lavender-top (EDTA) tube(s), (Do not centrifuge.) Freeze and ship frozen.
To avoid delays in turnaround time when requesting multiple tests, please submit separate frozen specimens for each test requested.
Note: Trofile DNA is recommended for patients with undetectable viral loads.
Specimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Frozen | 14 days |
Day(s) Performed
Sunday through Saturday
CPT Code Information
87999
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| FFTRO | Trofile DNA Phenotypic Corecept Tro | 53923-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| Z2283 | Tropotype Result | 53923-9 |
| Z2284 | Interpretation: | Not Provided |
Interpretation
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.
Nonreportable:
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.
Method Description
Co-receptor tropism is defined as an interaction of a virus with a specific co-receptor on the target cell. To gain entry into CD4+ cells, HIV must bind to the cell surface CD4 receptor and to one of two co-receptors, CCR5 or CXCR4. Trofile DNA uses the complete gp160 coding region of the HIV-1 envelope protein ensuring that all of the determinants of tropism tested.
Trofile DNA meets the US standards for technical validation as established by the Clinical Laboratory Improvement Amendments. Trofile DNA is a single cycle pseudovirion based tropism assay that uses the complete gp160 coding region of HIV-1 to evaluate tropism. Instead of using HIV-1 RNA isolated from patient plasma, Trofile DNA uses cell associated viral DNA taken from whole blood cells infected with HIV. HIV-1 envelopes encoded by the viral DNA are tested in a cell-based viral infectivity assay in order to determine which co- receptor the HIV-1 virus population is capable of using: CCR5, CXCR4, or both, known as D/M (dual/mixed).
Report Available
31 to 37 daysReject Due To
| Other | Insufficient volume; heparinized plasma; non frozen specimen |
Method Name
Polymerase chain reaction (PCR) amplification and viral culture.