Warfarin, Plasma
Use
This test is used to measure the concentration of Warfarin in plasma to guide dosage adjustments based on the International Normalized Ratio (INR) for prothrombin time. It is significant in managing and optimizing the therapeutic effect of Warfarin while minimizing the risk of bleeding or thrombosis. The peak plasma concentrations following standard doses provide crucial information for clinical management.
Special Instructions
Must submit one specimen per order. Specimens cannot be shared between multiple orders. Collection should be performed with specific humidity and temperature controls to ensure no degradation of the biospecimen.
Limitations
The test is not chiral specific and does not distinguish between the R and S enantiomers of Warfarin, which means it measures total Warfarin concentration. It may not accurately reflect patient response given these enantiomer-specific effects. Peak concentrations in plasma may require continuous monitoring and additional tests for accurate dose adjustments.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 4098-0
- 4098-0
Result Turnaround Time
9-11 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
EDTA (lavender top) or pink top; submission in plastic vial
Collection Instructions
Draw blood in EDTA or pink top tube(s). Plasma gel tube is not acceptable. Centrifuge and send 1 mL of plasma in a preservative-free vial refrigerated.
Storage Instructions
Refrigerate preferred
Causes for Rejection
Polymer gel separation tube (SST or PST)
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 30 days |
| Refrigerated | 30 days |