An advanced biochemical assessment specifically measuring the concentration of Phylloquinone (Vitamin K1) freely circulating in the blood serum. This critical, fat-soluble vitamin compound is physiologically irreplaceable for the complex hepatic synthesis of several major blood coagulation (clotting) factors. Additionally, Vitamin K plays a vital secondary biological role by regulating the structural formation, mineralization, and general integrity of bone tissues and related systemic connective tissue proteins.