Clinical Use: Vitamin K deficiency is found in patients with eating disorders or malabsorption and can lead to clotting disorders.
Background: Vitamin K is a nutrient that the body requires in small, regular amounts. It is essential for the formation of coagulation factors that work together to clot the blood when injuries to blood vessels occur. Insufficient vitamin K can lead to excessive bleeding and easy bruising. Vitamin K is also thought to play an important role in the prevention of bone loss. Low blood levels of vitamin K have been associated with low bone density, and there is some evidence that adequate levels of vitamin K can improve bone health while reducing the risk of fractures. There are three different types of Vitamin K:

  • Vitamin K1 (phylloquinone) is the type that comes from the diet, especially green leafy vegetables but also dairy products and vegetable oils.
  • Vitamin K2 (menaquinone) is made by bacteria, the normal flora in the intestines. It supplements K1, but there is not enough of it to meet the body’s requirements.
  • Vitamin K3 (menadione) is a synthetic water-soluble form of vitamin K that is used as a treatment for adults.

K1 and K2, the types provided by the diet and produced by the body, are both fat-soluble and are stored in the body’s fat tissue and in the liver. An adult typically stores about a week’s worth of vitamin K People who are on the anticoagulant drug Warfarin must be careful of the amount of vitamin K present in the foods that they eat. Vitamin K is an antagonist to Warfarin which is given to people with a variety of conditions such as deep vein thrombosis (DVT) and cardiovascular disease (CVD) to “thin” their blood and prevent inappropriate clotting. Rather than avoid foods rich in Vitamin K, it is more important for people on this drug to consume a consistent amount of Vitamin K each day.

Note that PIVKA-11, a sensitive marker of functional Vitamin K status, is also measured as a routine part of the profile – elevated levels suggest Vit K deficiency.

Reference Ranges: Vitamin K: 0.15 – 1.55 ug/L
Pivka11: 0.0 – 0.20 aU/mL
Associated Diseases:
Patient Preparation: Ideally collect venous blood after overnight fast
Specimen Requirements: Serum. – Red-topped tube or suitable anticoagulant e.g. heparin and separate serum.
IMPORTANT Vitamin K is highly light sensitive, protect from strong light at all times.
Turnaround Time: 2 weeks
Additional Information: Will also measure PIVKA 11 (sensitive marker of functional will also measure PIVKA 11 (sensitive marker of functional Vitamin K status with respect to gamma carboxylation status of coagulation factor F11). Sometimes also K10 (Vitamin K epoxide). PIVKA11, K10 elevated may suggest presence of Vit K antagonist. (PIVKA – Proteins Induced by Vitamin K Antagonism or Absence.) If patient on menadione (Vitamin K analogue) supplements Vitamin K will not be detected in serum but the functional marker PIVKA 11 would be corrected.
Referred Test: Referred test
Location: St Thomas’ Hospital