Vitamin K1 Test
This page explains the vitamin k1 test, what it measures, and how to arrange it. The Vitamin K1 test measures the amount of vitamin K1 (phylloquinone) in a blood sample. Vitamin K1 is a fat-soluble vitamin needed for normal blood clotting and bone health. This test is usually ordered when a person has unexplained bleeding or bruising, signs of poor nutrition, or a condition that affects how the body absorbs fats.
- Sample type
- blood
- Category
- Vitamin & Mineral
- Turnaround
- 1-3 business days
- Price
- $192
- Referral
- Not required
The Vitamin K1 test measures the amount of vitamin K1 (phylloquinone) in a blood sample. Vitamin K1 is a fat-soluble vitamin needed for normal blood clotting and bone health. This test is usually ordered when a person has unexplained bleeding or bruising, signs of poor nutrition, or a condition that affects how the body absorbs fats.
What it measures
- Vitamin K1 (phylloquinone) level — The main measurement; shows how much vitamin K1 is circulating in the blood.
- Prothrombin time (PT) — A clotting test often checked alongside vitamin K1 because vitamin K affects clotting.
- INR — A standardized version of PT that helps compare clotting results over time.
- Other fat-soluble vitamins — Sometimes vitamin A, D, or E are checked because they share similar absorption pathways.
- Liver-related tests — The liver stores vitamin K and makes clotting proteins, so liver markers may be included.
Who it is for
A clinician may order this test for people with easy bruising, unusual bleeding, suspected poor absorption of fats, or long-term use of certain medicines. It can also be used when a newborn or older adult shows signs of vitamin K deficiency.
Preparation
No fasting is usually required for a vitamin K1 blood test. Tell your clinician about all medicines, supplements, and recent vitamin K intake, because these can affect the result.
Results and what they mean
Results are reported as a number with a reference range, and the clinician interprets them alongside your symptoms and other tests. A low or high value does not by itself confirm a diagnosis. This is general information only and is not medical advice; discuss your results with a qualified healthcare professional.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the vitamin k1 test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast before this test?
Fasting is generally not needed. Follow any specific instructions your clinician gives you.
What can affect my vitamin K1 level?
Diet, vitamin supplements, some antibiotics, blood thinners, and conditions that affect fat absorption can change the result.
How long do results take?
Results are typically available within 1 to 3 business days, though timing can vary by lab.
Is this test the same as a vitamin K clotting test?
No. Vitamin K1 testing measures the vitamin level itself, while clotting tests such as PT and INR measure how well blood clots.