Vitamin K
Measures vitamin K levels to assess blood clotting function and evaluate potential deficiency that may affect bone health and coagulation.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
This test measures the blood level of vitamin K1 (phylloquinone), the primary dietary form of vitamin K found in green leafy vegetables and vegetable oils. Vitamin K belongs to a group of fat-soluble compounds that are essential for blood clotting, bone metabolism, and cardiovascular health. Its most critical role is serving as a cofactor in the production of several clotting factors (including factors II, VII, IX, and X) as well as anticoagulant proteins C, S, and Z, all of which require vitamin K to become functional.
Beyond coagulation, vitamin K contributes to bone health by activating osteocalcin, a protein involved in calcium binding within bone tissue, and it supports cardiovascular health by helping prevent calcium from depositing in arterial walls. Deficiency can lead to impaired blood clotting and increased bleeding risk. This test is ordered to evaluate suspected deficiency, assess clotting function, and investigate unexplained bleeding or bruising.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing unexplained bleeding, excessive bruising, or prolonged bleeding from minor cuts may benefit from vitamin K testing to evaluate potential deficiency.
- Those with malabsorption conditions such as celiac disease, Crohn's disease, cystic fibrosis, or liver disease should consider testing as these conditions can impair vitamin K absorption.
- Individuals taking long-term antibiotic therapy may need testing since certain antibiotics can disrupt gut bacteria that produce vitamin K or interfere with its metabolism.
- People with poor dietary intake of vitamin K-rich foods (green leafy vegetables, certain oils) or those following very restrictive diets may benefit from assessment of their vitamin K status.
- Adults taking anticoagulant medications like warfarin should discuss vitamin K testing with their healthcare provider to help monitor their nutritional status and medication effectiveness.
What to expect
Preparation
Fast for 12 hours before the blood draw and avoid alcohol for 24 hours prior. Avoid vitamin K supplements and vitamin K-rich foods for 24 hours before testing. Continue taking prescribed medications unless otherwise directed by your healthcare provider.
Sample Type
A healthcare professional will draw a blood sample from a vein in your arm using a standard needle and collection tube. The sample must be protected from light during collection and processing.
Collection
The blood draw typically takes just a few minutes at the lab location. No doctor visit required --- simply present your lab order and valid ID at the collection site.
Turnaround
Results are typically available within 7-10 business days and will be securely delivered through your online patient portal.
Understanding your results
Normal vitamin K1 levels for adults generally range from 0.10 to 2.20 ng/mL, though reference ranges can vary between laboratories and testing methodologies. Because vitamin K is fat-soluble and dependent on adequate dietary fat intake and absorption, results should be interpreted alongside dietary history, liver function, medications (particularly anticoagulants like warfarin, which work by blocking vitamin K activity), and any gastrointestinal conditions that may impair fat absorption. Healthcare providers may also consider coagulation studies (PT/INR) alongside vitamin K levels for a complete assessment of clotting function.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 0.10-2.20 ng/mL | Normal range for vitamin K1 (phylloquinone) levels in serum |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Vitamin K deficiency can contribute to significant bleeding, poor bone development, osteoporosis, and increased cardiovascular disease risk. The main symptom of vitamin K deficiency is excessive bleeding, which is the telltale sign of deficiency. Impaired blood clotting has been associated with vitamin K levels below 0.5 ng/mL. Low levels may be caused by inadequate dietary intake, malabsorption disorders, certain medications, or conditions affecting liver function.
What does a “High” result mean?
Elevated vitamin K levels may be associated with recent consumption of supplements or foods high in vitamin K, which can elevate plasma concentrations. Higher than normal levels are generally not considered harmful, as vitamin K is metabolized quickly and excreted in urine or stool and typically doesn't reach toxic levels even with high intakes. Elevated levels might indicate recent dietary intake of vitamin K-rich foods or supplementation.
Privacy & confidentiality
Your vitamin K test results are completely confidential and protected under HIPAA regulations. Results are not shared with your personal physician unless you choose to do so, are not added to your medical record, and do not appear on insurance explanations of benefits since no doctor visit is required.
Frequently asked questions
Related tests
Coagulation Panel
Evaluates overall blood clotting function and complements vitamin K assessment
View TestVitamin D
Works synergistically with vitamin K for optimal bone health and calcium metabolism
View TestVitamin B12
Part of comprehensive nutritional assessment for individuals with suspected deficiencies
View TestLiver Panel
Assesses liver function, which is important for vitamin K metabolism and storage
View TestLast reviewed: April 2026
CPT Code: 84597
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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