Monitoring vitamin K status helps to reduce the risk of osteoporotic fractures and cardiovascular disease. Our body’s vitamin K status can be directly measured by observing the level of inactive (also known as uncarboxylated) osteocalcin in blood. It is difficult for doctors to directly identify the vitamin K2 in the blood, because the vitamin K consumed by the human body is very small and is stored in the body. Therefore, the state of vitamin K2 can be more accurately reflected by the level of vitamin K dependent protein (such as osteocalcin). High level of inactive osteocalcin reflects lower vitamin K2 status, meanwhile more active osteocalcin suggests sufficient vitamin K2 state.