There are various tests to determine if there is a calcium deficiency. You can test for trace elements through blood, the main one of which is to check the calcium level in the blood. If the blood calcium level drops, the body will divide the calcium from the bones into the blood to maintain a stable blood calcium level in the body, thus ensuring the stability of the internal environment. The next test is by urine. Calcium in urine is not only related to calcium intake, but also subject to usual dietary factors. However, this test is affected by urine volume and kidney function, and sometimes shows that increased calcium intake may also be due to kidney pathology. The last one is through bone density test, which is the most accurate one and can reflect the degree of calcium deficiency in bones, because the minerals in human body mainly constitute structures such as bones, so almost all the calcium in human body exists in bones and teeth, which are the main components of bones and teeth, and bone density test can accurately reflect the calcium reserve of human body.