25 Hydroxyvitamin D is a form of vitamin D found in the body and is a common fat-soluble vitamin. It is converted to vitamin D by the liver through hydroxylation and has the function of regulating calcium and phosphorus metabolism in the body.25 Hydroxyvitamin D is a very direct response indicator to know the body’s vitamin D storage, and the normal value is generally 30-100ng/L. If 25 hydroxyvitamin D is lower than normal, it means that the body’s vitamin D level is insufficient and needs to be supplemented in time. If the 25 hydroxyvitamin D is lower than the normal value, it means that the body’s vitamin D level is insufficient and needs to be supplemented in time. Vitamin D deficiency may lead to rickets, osteomalacia and other diseases. On the contrary, it indicates that too much vitamin D is accumulated in the body and its intake needs to be reduced. The patient experiences nausea, vomiting, limb weakness, insomnia, frequent urination, dry mouth and other physical discomforts. If the patient has an abnormality of 25 hydroxyvitamin D, it is recommended to go to the hospital in a timely manner, to clarify the cause of the disease, and then corrected under the guidance of the doctor.