Vitamin K
Use
Vitamin K is a required co‑factor for the synthesis of clotting factors II, VII, IX, and X as well as proteins C and S. Deficiencies lead to bleeding and warfarin functions as a vitamin K antagonist, impairing clot formation.
Special Instructions
Patient must fast for at least 8 hours and refrain from consuming liver or taking multivitamins or vitamin K for at least 24 hours before collection. Protect specimen from light. Centrifuge within 1 hour and freeze immediately in an amber tube or wrap to protect from light. Frozen plasma preferred; frozen serum acceptable.
Limitations
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics and validated under CLIA regulations. It has not been cleared or approved by the FDA.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 9622‑2
Result Turnaround Time
3-4 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL preferred (0.5 mL minimum)
Minimum Volume
0.5 mL
Container
EDTA (lavender‑top) tube (also sodium or lithium heparin tube acceptable)
Collection Instructions
Protect from light; centrifuge within 1 hour; separate plasma into amber transport tube or wrap in foil; freeze immediately; do not thaw
Patient Preparation
Fasting minimum 8 hours; avoid liver and vitamin K/multivitamins for 24 hours prior
Storage Instructions
Frozen
Causes for Rejection
Gross hemolysis; grossly lipemic; thawed specimens or unprotected from light
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 24 hours |
| Frozen | 90 days |