An alkaline phosphatase of 250 U/L is normal in a 3-year-old child. Serum alkaline phosphatase is higher in children than in adults, and the normal value is less than 350 U/L by the enzyme rate method and less than 500 U/L by the dynamic method; either way, 250 U/L alkaline phosphatase is within the normal range. Alkaline phosphatase is a group of enzymes that are widely distributed in many parts of the body, including the bones, liver, kidneys, and intestines. Normal values in adults are 40 to 160 U/L measured by the enzyme rate method and 20 to 110 U/L measured by the dynamic method. Adults are lower than children because children are in the process of rapid development, so the alkaline phosphatase in the body will be higher than adults, which is a physiological increase. Alkaline phosphatase 250U/L in 3-year-old children is normal, parents do not need to worry too much, if you still have doubts, you can go to the hospital.