Serum vitamin determination is to determine whether the concentration of various vitamins in the serum is within the normal range, because vitamins are very important for maintaining normal physiological functions of the body, and at the same time, the normal physiological functions of the body can only function normally if the vitamin concentration is kept within the normal range. If the concentration of vitamins is too high or too low, some pathological conditions can occur. For example, there is a normal range for the concentration of vitamin B12, and if the concentration of vitamin B12 is reduced, it can cause pernicious anemia and megaloblastic anemia. By the same token, folic acid, a B vitamin, may also induce megaloblastic anemia if the concentration of folic acid decreases. If the concentration of vitamin A decreases, the patient may develop night blindness. If the concentration of vitamin C decreases, the patient may develop scurvy. Therefore, the measurement of vitamin concentrations provides an understanding of whether the body’s vitamin concentrations are within the normal range and is used to guide clinical treatment.