AccuType® Warfarin

Test Code

16160

CPT Codes
81227, 81355

Physician Attestation of Informed Consent

This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.

Includes

detects variants from two genes, VKORC1 and CYP2C9

Preferred Specimen

5 mL whole blood collected in an EDTA (lavender-top) tube, or ACD-A or B (yellow-top) tube

Minimum Volume

3 mL

Other Acceptable Specimens

Whole blood collected in a sodium heparin or lithium heparin (green-top) tube, or sodium heparin (royal blue-top) tube

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 8 days
Refrigerated: 8 days
Frozen: Unacceptable

Methodology
Single Nucleotide Primer Extension

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Monday, Wednesday, Friday Morning Report available: 7 Days

Limitations

Variations in two genes (VKORC1 and CYP2C9) are particularly important in warfarin metabolism. VKORC1 may explain 30% of the variability in drug response between patients and changes in CYP2C9 may explain 10% of the dose variation. While significant portion of the dose variability can be accounted for by genetic factors, this testing will not determine all factors associated with dose variability.

Reference Range

See Laboratory Report

Clinical Significance

Warfarin (Coumadin^®) therapy is associated with significant complications because of its narrow therapeutic index and large interpatient dosage variation necessary to achieve an optimal therapeutic response. This variation is due to both genetic and environmental factors. A promoter variant (-1639 G→A) of the Vitamin K epoxide complex subunit 1 (VCR) accounts for 25%-44% of this variability and variants of the cytochrome P enzyme C (SPCA) account for 10%-15% of this variability. Identification of these warfarin sensitive variants of the VKORC1 and the CYP2C9 genes may allow a more individualized therapy and reduced risk of bleeding complications.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.