Alkaline phosphatase in the blood
Last reviewed: 23.04.2024
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Alkaline phosphatase is widely distributed in human tissues, especially in the intestinal mucosa, osteoblasts, the walls of the bile ducts of the liver, the placenta and the lactating mammary gland. It catalyzes the cleavage of phosphoric acid from its organic compounds; its name is due to the fact that the optimal pH of this enzyme is 8.6-10.1. The enzyme is located on the cell membrane and takes part in the transport of phosphorus. For diagnostic purposes, the activity of bone and liver forms of alkaline phosphatase is most often performed.
Reference values (norm) of activity of alkaline phosphatase in serum (reaction with phenylphosphate)
Age |
Total, IU / L |
Bony,% |
Newborns |
35-106 | |
1 month |
71-213 |
85 |
3 years |
71-142 |
85 |
10 years |
106-213 |
85 |
Adults under the age of 31 |
39-92 |
60 |
Adults over the age of 31 |
39-117 |
40 |
Bone alkaline phosphatase produces osteoblasts - large single-nucleated cells lying on the surface of the bone matrix in places of intense bone formation. Apparently, due to the extracellular location of the enzyme in the process of calcification, it is possible to trace the direct relationship between bone disease and enzyme activity in serum.