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HelpTest Code LAB20430 Trofile Co-Receptor Tropism Assay
Reporting Name
Trofile Phenotypic Corecept TropismUseful For
Detect HIV-1 coreceptor tropism; determine eligibility for CCR5 antagonist therapy such as maraviroc (Selzentry)
Performing Laboratory
Monogram Biosciences, IncSpecimen Type
Plasma EDTASpecimen Required
Specimen Type: Plasma
Container/Tube: Lavender-top (EDTA) or plasma preparation tube (PPT)
Specimen Volume: 3 mL
Collection Instructions: Draw blood in either PPT (pearl top) or lavender-top (EDTA) tubes.
Centrifuge specimen within six hours of collection. Remove plasma from cells immediately, and transfer specimen to a screw-capped, plastic vial. Freeze 3 mL of PPT plasma or EDTA plasma immediately, send specimen frozen.
To avoid delays in turnaround time when requesting multiple tests, please submit separate frozen specimens for each test requested.
RECOMMENDED:
1. Patient's most recent viral load
2. Viral load collection date
Note: 1. Intended to use only for patients with viral loads greater than or equal to 1000 copies/mL. For best results, viral loads should be confirmed within two weeks prior to submission for testing at Monogram.
2. Patient samples submitted <30 days apart are considered duplicate and will be cancelled.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma 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 |
|---|---|---|
| FFTRP | Trofile Phenotypic Corecept Tropism | 57182-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| Z1038 | Tropotype Result | 57182-8 |
| Z1039 | Note: | Not Provided |
| Z1040 | Activity of CCR5 antag anticipated? | Not Provided |
Interpretation
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 CCR5 or CXCR4 to enter CD4+ cells. Mixed-tropic populations contain viruses with two or more tropisms.
Non-reportable
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.
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 is a cell-based approach to determine a patient’s HIV co-receptor tropism (or Tropotype). Trofile uses the complete gp160 coding region of the HIV-1 envelope protein ensuring that all of the determinants of tropism are tested. CLIA validation experiments demonstrate that Trofile is 100% sensitive at detecting 0.3% CXCR4-using minor variants.
This class of drugs binds to CCR5 and blocks CCR5-mediated HIV entry into host cells. Trofile is used to determine whether a CCR5 antagonist may be an appropriate drug for a patient. Several clinical trials on CCR5 antagonists have demonstrated the positive and negative predictive value of Trofile in clinical settings.
Report Available
29 to 39 daysReject Due To
| Other | PPT not centrifuged; insufficient volume; heparinized plasma; non frozen specimens |
Method Name
Polymerase chain reaction (PCR) amplification and viral culture.