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Warfarin, Plasma

Coumadin

Test Codes

Mayo: FWARP, EPIC: LAB6185, Beaker: XWARL

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One Lavender-top EDTA tube.

Do not use Plasma Separator Tubes.

Physician Office/Draw Specimen Preparation

Centrifuge to separate plasma from cells. Transfer plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL plasma, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

Plasma Separator (PST) tubes.

Specimens not collected and processed as indicated.

In-Lab Processing

Centrifuge to separate plasma from cells. Transfer plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 1.0 mL plasma, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 14 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN. Forwarded to National Medical Services (NMS), Willow Grove, PA.

Performed

Monday – Sunday
Results available in 8-11 days.

Reference Range

By report.

Test Methodology

Quantitative High Performance Liquid Chromatography – Tandem Mass Spectrometry.

Interpretation

By report.

Clinical Utility

Warfarin is an anticoagulant drug used to treat venous thrombosis, pulmonary embolism, atrial fibrillation with embolization, and transient cerebral iscemic attacks. This assay is used for monitoring patients whose prothrombin time is inconsistent with the prescribed warfarin dose, particularly when failure to comply or unauthorized drug use is suspected.

CPT Codes

80375
LOINC:  4098-0, 31208-2

Contacts

Last Updated

7/19/2021