Vitamin K Assay - Serum

The Many Functions of Vitamin K

Additional resources:

• Vitamin K White Paper
• Vitamin K Patient Information Sheet

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

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: