The difference between blood calcium and bone calcium is mainly reflected in the following aspects: 1. The form of existence is different. Calcium in the blood mainly exists in the form of ionic calcium salts. In contrast, calcium in bone exists mainly in the form of compounds such as calcium carbonate and calcium phosphate. 2, the content is different. Although the content of calcium salts in blood seems to be higher, its calcium content is much lower compared to that in bone. Bone is the body’s storehouse of calcium and phosphorus. 3, the stability is different. The calcium content of the blood fluctuates greatly with the body’s metabolism. For example, when a patient vomits, has diarrhea or sweats a lot, the calcium level in the blood may drop dramatically for a short period of time. In addition, if the patient eats food high in calcium, it may also cause a short time rise in calcium salts, while the change in calcium in the bone is relatively moderate. 4, the form of supplementation is different. Calcium in the blood can be supplemented by food. In addition, when the calcium salt in the blood drops for a short time, the calcium salt in the bone can be released into the blood for a short time. The calcium in the bone, however, can only be deposited gradually into the bone through the calcium salts in the blood.