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Vitamin K

Vitamin K is a fat-soluble vitamin that plays an important role in blood clotting and bone building. Two variants are known, phytomenadione (vitamin K1) found in green plants and menaquinone (vitamin K2) produced by intestinal bacteria.

The body provides the essential amount of vitamin K from these two types: vitamin K1, extracted from ingested food, and vitamin K2, produced in the gut by intestinal bacteria. With proper nutrition and healthy intestinal flora, the body’s vitamin K supply can be maintained.

Vitamin K1 is essential to activate blood clotting factors, which block the bleeding by closing the opening on the vessel wall in case of an injury. In its absence, hemophilia may develop.

Vitamin K2 plays an important role in keeping bone density at an appropriate level. Its deficiency reduces the level of active osteocalcin, thus increasing the chance of developing bone fractures and osteoporosis. Maintaining adequate levels of vitamin K2 in women in the climacteric period is, therefore, crucial to preserve bone density.

Vitamin K1 is found in large amounts in green leafy plants such as spinach, broccoli, lettuce, cabbage, kale, and in eggs and milk. A natural source of vitamin K2 are foods made by bacterial fermentation, such as matured cheeses.

What does the test show?

The test can be used to measure the levels of vitamins K1 and K2 in the blood, which can be used to determine a deficiency or a possible overdose.

In what cases is it recommended to perform the test?

Laboratory testing of vitamin K levels is recommended in case of suspicion of vitamin K deficiency or overdose, based on symptoms.

The following symptoms may indicate a lack of vitamin K:

  • slow blood clotting in case of an injury
  • small bruises also cause extensive bruising
  • frequent nose bleeding
  • blood in the urine
  • low prothrombin activity
  • osteoporosis

Deficiency can also be caused by liver disease, Crohn’s disease, unilateral diet, cholesterol-lowering drugs, and antibiotics


Vitamin K overdose is not associated with toxical symptoms but may cause an allergic reaction (hives, difficulty breathing), blood pressure and blood clotting problems, stomach complaints, and may affect the effects of other medications.

What kind of sample is needed for the test?

A blood sample, taken from a vein, is needed to perform the test.

What could the result indicate?

When vitamin K levels are within the normal range, the amount of vitamin K needed in the body to clot and preserve bone structure, is provided.

A result below the normal range indicates a lack of the given vitamin K. As vitamin K supplementation may affect the effects of blood thinners and anticoagulants, always consult your doctor to determine the appropriate therapy.

A value above the normal range indicates an overdose, which may have long-term hepatotoxic effects.

What to do after the test?

The result itself doesn’t constitute a diagnosis, therefore always consult your doctor or the specialist who ordered the examination to set the diagnosis and determine the treatment required.

Üzenjen nekünk!