Vitamin K is a fat-soluble vitamin that functions as a cofactor in the production of blood coagulation factors (in the liver), osteocalcin (in bone), and matrix Gla-proteins (in cartilage and vessel walls), each resulting in the deposition of ionic calcium.
Monitoring vitamin K can help reduce risk of osteoporotic bone fractures, cardiovascular disease, and possibly some cancers by identifying individuals who may have a vitamin K deficiency. Since current dietary recommendations of vitamin K are based on saturation of the coagulation system, those recommendations may be insufficient to maintain vascular and bone health, since individual functions are independent of each other.
Vitamin K status is especially important in individuals:
- With cardiovascular disease or those with a family history of arteriosclerosis
- At high risk of bone loss, such as pre- and post- menopausal women or those with a family history of osteoporosis
- On certain drug therapies, particularly blood thinners, such as warfarin or aspirin
- On restricted diets
- On long-term antibiotic therapies
The Metametrix Vitamin K Assay
Direct vs. functional measurement of vitamin K
The Metametrix Vitamin K Assay measures a functional marker, undercarboxylated osteocalcin (ucOC). Very little vitamin K is stored in the body therefore direct measurement is not ideal.
Osteocalcin (OC) is almost exclusively a product of mature, active osteoblasts and is a vitamin K-dependent, Ca+2 binding protein. A vitamin K deficiency is indicated by an ucOC increase in circulating blood and urine. Therefore, high ucOC indicates low vitamin K status.
Symptoms & conditions related to vitamin K deficiency:
- Bruising
- Epistaxis
- Fractures
- Gastrointestinal bleeding
- Menorrhagia
- Hematuria
- Nosebleeds
- Anemia
- Osteopenia/Osteoporosis
- Calcification of soft tissue, especially heart valves
- Digestive problems, especially malabsorption
- Cardiovascular Disease
- Cancer
- Malabsorption syndromes
Increasing vitamin K
There are two natural forms of vitamin K, which differ based on their phytyl group-phylloquinone (vitamin K1) synthesized from plants, and menaquinone (vitamin K2) from bacteria in the large intestines.
- Vitamin K1 is highest in green leafy vegetables such as kale, broccoli, collard greens, and lettuce.
- Vitamin K2 is found in fermented foods such as cheese, meats, and dairy products.
- Use salicylates such as aspirin with care. Salicylates can block vitamin K.
- Vitamin K supplements
Test name(s)
0031 - Vitamin K Assay*
Description
Vitamin K is a fat-soluble vitamin that functions as a co-factor in the production of blood coagulation factors (in the liver), osteocalcin (in bone), and matrix Gla-proteins (in cartilage and vessel walls) each resulting in the deposition of ionic calcium. The Vitamin K Assay measures the functional marker, undercarboxylated osteocalcin, to determine vitamin K status. Vitamin K deficiency can lead to an increased risk of bone loss or fracture.
Method
EIA
Turnaround time
10 days
Analytes
Undercarboxylated osteocalcin
*Not available in New York
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