Vitamin K → Clotting Factors → PT / INR
The biology
Vitamin K is essential for the liver to make active clotting factors II, VII, IX and X. Without enough vitamin K, those factors do not work properly — blood takes longer to clot, PT rises and so does INR.
What this means
Risk of easy bruising or bleeding. Could come from diet, gut absorption problems, broad-spectrum antibiotics, or medications like warfarin.
Advice
Eat green leafy vegetables, broccoli and liver. If you are on warfarin, keep vitamin K intake steady rather than going on and off greens. Check medication interactions with your pharmacist.
Tests in this chain