|Values are valid only on day of printing.|
Assessment of circulating vitamin K1 concentration
Vitamin K1 or phylloquinone is part of a group of similar fat soluble vitamins in which the 2-methyl-1,4-naphthoquinone ring is common. Phylloquinone is found in high amounts in leafy green vegetables and some fruits (avocado, kiwi). It is a required cofactor involved in the gamma-carboxylation of glutamate residues of several proteins. Most notably, the inactive forms of the coagulation factors prothrombin (factor II), factors VII, IX, and X and protein S and protein C are converted to their active forms by the transformation of glutamate residues to gamma-carboxyglutamic acid (Gla). Other proteins such as those involved in bone metabolism, cell growth, and apoptosis also undergo this Gla transformation. Measurement of vitamin K1 (phylloquinone) in fasting serum is a strong indicator of dietary intake and status.
> or =18 years: 0.10-2.20 ng/mL
<18 years: not established
Low vitamin K1 concentrations in the serum are indicative of insufficiency and poor vitamin K1 status.
1. Vermeer C: Vitamin K: the effect on health beyond coagulation-an overview. Food Nutr Res 2012;56:5329
2. Lippi G, Franchini M: Vitamin K in neonates: facts and myths. Blood Transfus 2011;9:4-9
3. Greer FR: Vitamin K the basics-What's new? Early Hum Dev 2010;86:S43-S47