Blood draw
Vitamin K1 and K2
Vitamin K1 and K2; coagulation and bone health.
€ 125,00
All tests
Vitamins, minerals and amino acids · Blood
Vitamin K1
The amount of vitamin K1 in the blood; mainly reflects intake over the last few days.
At a glance
- Measured in blood
- In 1 test panel
- Check the preparation
Explanation
Vitamin K1: what is measured?
Vitamin K1 (phylloquinone) comes mainly from green leafy vegetables, vegetable oils, milk, meat and fish. The liver uses vitamin K1 to activate clotting factors II, VII, IX and X, the proteins that make the blood clot when there is bleeding. The stores are in the liver and last for about two months. What the laboratory measures is the amount in the blood at that moment, and that fluctuates strongly with what you have eaten in the past few days.
What can it detect?
- A vitamin K1 deficiency due to poor absorption of fats, for example with a bile duct problem, a poorly functioning pancreas or a liver disease
- A very low intake, for example with a long-term one-sided diet or anorexia nervosa
Result
What does the result mean?
Vitamin K1 too high
A high value is almost always caused by a meal with a lot of green vegetables shortly before the blood draw or by a supplement. According to the Dutch Society for Clinical Chemistry (NVKC), a high vitamin K1 has little to no meaning. There are no known symptoms that go with a high value. However, a supplement with a lot of vitamin K does matter for anyone using a coumarin-type blood thinner, because it disturbs the dose setting.
Vitamin K1 too low
A low value may fit a low intake or reduced absorption of fats from the gut, for example due to a problem with bile drainage, the pancreas or the liver. In adults in the Netherlands a true deficiency is rare. A low value on its own says little about clotting: for that the laboratory looks at the prothrombin time (PT or INR), which measures how much clotting function remains. A low value can also simply mean that you ate few green vegetables in the days before the blood draw.
After an abnormal result
With a low value, the GP first looks at clotting (PT or INR) and at reasons why fats are poorly absorbed, such as a liver, bile or pancreas problem or a bowel disease. With a tendency to bleed or a strongly prolonged clotting time, referral to an internist (specialist in internal medicine) follows.
Reliability
How reliable is the test?
For vitamin K1 in blood there are no agreed cut-off values below which a deficiency is diagnosed, and the meaning of a slightly abnormal value in people without symptoms has been little studied. The value in the blood follows the intake of the last few days and says little about the stores in the liver or about its action in the body. The result is mainly informative when a cause is being sought for bleeding or a prolonged clotting time. What vitamin K does functionally is better read from the clotting test (PT or INR) than from the level.
What can affect the result?
- The value fluctuates strongly with the diet of the last few days and with the fat intake at the meal; there is no fixed fasting rule for it.
- Coumarin-type blood thinners (acenocoumarol, phenprocoumon) block the action of vitamin K and not the level: the result then says nothing about clotting, while extra vitamin K actually disturbs the dose setting of these medicines.
- Vitamin K1 is fat-soluble and sensitive to light; delayed or unprotected transport lowers the measured value, and fatty (cloudy) serum disturbs the measurement.
- Measurement methods and reference values differ per laboratory.
Preparation
- Do not eat anything for 12 hours before the sample is taken and drink only water. Vitamin K1 enters your blood with fat from your food, so the value is higher after a meal.
Who it is for
Who is the test useful for?
Useful for
The result is mainly informative with an unexplained tendency to bleed or a prolonged clotting time, and with diseases in which fats are poorly absorbed. In adults without symptoms and with a varied diet the value adds little. Anyone using a coumarin-type blood thinner gains nothing from this test: the effect of those medicines is read from the INR, not from the vitamin K level.
How common is it?
A vitamin K1 deficiency is rare in adults in the Netherlands, because the vitamin is found in many foods and gut bacteria also contribute to it. Newborns do often have low stores; that is why in the Netherlands they are routinely given vitamin K drops. In adults a deficiency occurs mainly with long-term problems with fat absorption.
NVKC, allesovertesten.nl and Netherlands Nutrition Centre (Voedingscentrum)
Drawbacks and risks
- A low value without clotting problems usually means nothing and can cause unnecessary worry or lead to unnecessary further testing.
- A low result can lead people to start taking vitamin K themselves; when using a coumarin blood thinner, this is dangerous for the dose setting.
Get tested
Vitamin K1: test panels
Vitamin K1 is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and resultsMore explanations
Other tests: Vitamins, minerals and amino acids
- AC/FC ratio
- Acylcarnitine
- Alanine
- Antibodies against intrinsic factor
- Arginine
- Calcium
- Calcium (albumin-corrected)
- Carnitine, free
- Carnitine, total
- Coenzyme Q10
- Copper
- Folic acid