Alkaline phosphatases are enzymes present in various tissues of the body. Alkaline phosphatase levels change with age, although alkaline phosphatase changes may be related to obstructive bile duct problems in the liver and some bone disorders. But healthy children may also have an increase in blood alkaline phosphatase levels due to the speed of bone growth. This increased alkaline phosphatase in healthy children is called transient hyperalkalinphosphatemia.


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What is Alkaline Phosphatase?

In the human body, the enzyme alkaline phosphatase is present in the mucosa of the end of the small intestine (ilium), kidneys, liver, bones and placenta in pregnant women.

There is a level of alkaline phosphatase in our blood that is 80% of the source of this alkaline phosphatase in the liver and bones. Alkaline phosphatases at the end of the small intestine and placenta are called tissue alkaline phosphatases, which are not present in the bloodstream in healthy people.

Alkaline phosphatases in the blood are called independent alkaline phosphatases that originate in the liver, bone (up to eighty percent) and kidneys.


Reasons for increased serum alkaline phosphatase

Usually in most adults, liver damage is responsible for high ALP levels



  1. Bone disorders and problems such as:


  1. Normal growth and increased bone structure in adulthood:

High alkaline phosphatase is seen in healthy children and adolescents as they grow older that is called Transient hyperalkalinphosphatemia

A special type of alkaline phosphatase that is produced exclusively by bones is called ALP 2 isoenzyme. That is, when doctors see that a child has high blood alkaline phosphatase, to determine that the reason for this increase is due to increased growth and bone structure and has nothing to do with the liver and kidneys.

By specialized tests, this special type of alkaline phosphatase is isolated and tested in special methods. These diagnostic tests for bone-derived alkaline phosphatase, or ALP 2, are:


What is the normal blood level for bone alkaline phosphatase?

This value will be 7.42-1.21 in adults and higher in children

Also, healthy adults with fractured bone fractures can naturally have higher levels of this enzyme.

Of course, the bone enzyme increase test alone is not enough to diagnose the type of disorder, and other tests should be done as well.


Causes of high phosphatase in children

TH is a completely normal and non-morbid condition in children of bone age.

Under these conditions, the child has no systemic signs of a disorder or disease, is healthy, and Only the blood level of alkaline phosphatase is high and with the more specific tests mentioned above, it is clear that the source of most of this high alkaline phosphatase in children is bone. This transient elevated alkaline phosphatase is common in infants and children and rarely occurs in adults. Except in adults with improving bone fractures.

Blood levels of alkaline phosphatase are usually related to age. After the age of five, and more generally after the age of fifteen, when height growth slows down, blood levels of alkaline phosphatase decrease.

In adults, elevated alkaline phosphatase is more commonly studied in the field of liver problems and bone problems and tumors.


So far, we have identified the reason for the increase in alkaline phosphatase in healthy children without disorders

Other reasons for increased alkaline phosphatase in children that are related to liver and bile duct problems include:

The most common group in this group is bile duct atresia. Bile duct atresia is slightly more common in girls than in male infants.

The bile duct may not be formed at all during pregnancy or the bile duct may form but be damaged and inefficient due to injury such as some infections.


Even healthy infants, babies, and children can develop acute liver failure in response to metabolic disorders or certain medications.

These children develop sudden jaundice and may also have a fever and vomiting. The blood levels of the enzyme alkaline phosphatase are high in these children. These children should be rushed to a well-equipped pediatric treatment center. Twenty-four hours of intensive care is required.

It should be noted that more than sixty percent of infants born during preterm labor (before 30 weeks) will have liver and bile duct defects.


Symptoms of liver failure in children

A child with liver problems may show the following clinical manifestations:

If your baby or toddler has high clinical manifestations, do not waste time visiting neonatal and pediatric care centers.