Vitamin K
Vitamin K testing is utilized primarily to evaluate:
- Vitamin K deficiency: Vitamin K deficiency can lead to impaired blood clotting and an increased risk of bleeding. Vitamin K testing helps diagnose deficiency, particularly in individuals with conditions or factors that can affect vitamin K absorption, synthesis, or utilization. These may include malabsorption disorders (such as celiac disease or inflammatory bowel disease), long-term antibiotic use, liver disease, or certain medications (such as anticoagulants).
- Assessment of coagulation status: Vitamin K is essential for the synthesis of clotting factors in the liver, including prothrombin (factor II), factors VII, IX, and X. Vitamin K testing, along with other coagulation tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT), aids in assessing coagulation status and identifying abnormalities in the clotting cascade.
- Monitoring of anticoagulant therapy: Vitamin K antagonists (e.g., warfarin) are commonly used as anticoagulant medications to prevent blood clots in individuals at risk of thromboembolic events. Vitamin K testing may be performed to monitor the effects of anticoagulant therapy and assess the risk of bleeding. Changes in vitamin K levels can affect the efficacy and safety of anticoagulant treatment.
- Evaluation of newborns: Newborn infants are at risk of vitamin K deficiency bleeding (VKDB) due to low vitamin K levels at birth and limited transfer of vitamin K across the placenta. Vitamin K testing may be performed in newborns to assess vitamin K status and guide recommendations for vitamin K supplementation to prevent VKDB.
- Evaluation of liver function: Vitamin K is involved in the synthesis of certain proteins in the liver, including clotting factors and proteins involved in bone metabolism. Vitamin K testing may be used as part of the evaluation for liver disease or to assess liver function in individuals with liver disorders.