Vitamin K Deficiency Workup

Updated: Sep 27, 2017
  • Author: Dieu-Thu Nguyen-Khoa, MD, FACP; Chief Editor: George T Griffing, MD  more...
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Laboratory Studies

Measurements of serum prothrombin time (PT) tend to be elevated and activated partial thromboplastin time (aPTT) is usually normal. [8]  Both PT and aPTT can be elevated in more severe deficiency states.

The most sensitive marker that is elevated in VK deficiency states is des-gamma-carboxy prothrombin (DCP), also known as protein induced by vitamin K absence/antagonist-II (PIVKA-II). [9]  PIVA-II levels reflect the functional marker of coagulation.

The plasma level of VK, serum phylloquinone, (0.2-1.0 ng/mL) can be measured; however, the level of VK depends on the oral intake of VK, which can vary. However, a low serum phylloquinone (< 0.15 mcg/L) suggests low tissue body stores. [19]

A clearly prolonged PT (INR > 3.5) along with normal fibrinogen concentration and platelet count is highly suggestive ofvitamin K deficiency-related bleeding (VKDB). Confirmation of the diagnosis requires measurement of the specific vitamin K-dependent factors (II, VII, IX, X) whose levels are rapidly corrected by the parenteral administration of 1 mg vitamin K. [3]