Alkaline Phosphatase, an enzyme found in various tissues throughout the body, including the liver, bone, kidneys, intestines and in pairs of pregnant women. This test with other common names like ALK PHOS; Alkp is also called.

ALP is an enzyme that is mainly produced in the liver and bone marrow, and the enzyme is extracted from the intestine, kidney, and pairs.
ALP testing is helpful for diagnosing liver and bone diseases. In cases of mild liver damage, ALP levels may only slightly increase. But in acute liver disease, it can be increased dramatically. As soon as the transition from the acute phase, the serum level suddenly decreases, while the bilirubin will remain high.
Several laboratory tests have been performed to determine liver dysfunction (for example, bilirubin, leucine amino-peptidase (LAP), 5- nucleotidase and gamma glutamyl terep peptidase)
In bone disorders, ALP levels increase due to the activity of osteoblasts (abnormal bone marrow production). In children, finding high levels of ALP prior to puberty is unnatural due to bone growth.

The ALP iso-enzymes are used to differentiate between liver and bone diseases, ALP1 represents hepatotoxicity and bone marrow ALP2.

● Purposes of alkaline phosphatase testing:
Determine if there is a liver or bone disorder
- Compare ALP results with other laboratory tests to confirm your liver or bone disorder.

● The cause of the test request:
For screening or monitoring, treatment for liver or bone disorders is also required as part of the liver routine panel or when a person has symptoms of liver or bone disorders.
This test may also sometimes be used to monitor the treatment of Paget's disease or other bone conditions, such as vitamin D deficiency.

● Reference range:
The reference values ​​depend on the measurement method and the test. The normal values ​​are higher in children and pregnant women. In children, the normal values ​​are 2 to 3 times that of adults and peak at puberty.
During very rapid episodes of growth and development, values ​​above U / L1000 may be normal. High levels of alkaline phosphatase in childhood indicate osteoblastic activity and bone growth, and after puberty, the origin of alkaline phosphatase is often liver.
Natural values ​​in adults are approximately 50- 120 U / L. During pregnancy, the natural rate is almost double that amount.
Normal values ​​in mature males are slightly higher than in women. After menopause, normal values ​​are equal or greater than that of men.

● Under what conditions the test will increase:
Increasing ALP levels in the blood is usually caused by liver disease or bone disorders. The levels of this enzyme can be greatly increased, for example in cases where one or more bile ducts have been blocked. Increased levels of this enzyme are found in liver and cirrhosis, using toxic liver and hepatitis drugs. Any condition that results in excess bone formation, including bone diseases such as Paget's disease and other diseases, such as rheumatoid arthritis, and fracture improvement can increase ALP levels. Children and teens typically have higher ALP levels, because their bones are still growing.
Pregnancy can increase ALP levels. With the improvement of fractures, temporary increase is also observed.

● Under what conditions the test is reduced:
If the treatment of a Paget's disease is successful, the ALP level decreases or returns to normal. If an individual with bone or liver cancer responds to treatment, the ALP should be reduced.
Low levels of ALP may be seen temporarily after a blood transfusion or post-operative heart surgery. Zinc deficiency may reduce ALP levels. A rare genetic disorder of bone metabolism, called hypophosphatosia, can lead to severe and prolonged levels of ALP levels.
High ALP usually means that either the liver is damaged or conditions that increase the activity of bone marrow cells.
If other liver tests such as bilirubin, aspartate aminotransferase (AST) or alanine aminotransferase (ALT) are high, ALP is usually from the liver.
If calcium and phosphorus are abnormal, usually ALP is bone. If GGT or 5'-Nucleotidease is also increased, high ALP is probably due to liver disease.
If either of these two tests is normal, the ALP is high, probably due to bone condition.
If it is not clear from signs and symptoms or from other routine tests that high ALP is due to liver or bone, testing for ALP isoenzymes may need to differentiate between ALP of bone and liver.

● Additional tests:
AST; ALT; GGT; Bilirubin; Liver panel; Bone markers; Alkaline phosphatase isoenzymes; Bone specific ALP

Differential Diagnosis:
If the ALP results are increased, but it is unknown whether this is due to liver or bone disease, the first test for testing the ALP isozyme should be done to determine the cause.
GGT testing or 5'-nucleotide test may also be used to differentiate between liver and bone diseases. GGT levels and 5'-nucleotide levels increase in liver disease but do not increase bone abnormalities.
Readiness for testing

● Drug Interactions:
Some medications may affect the level of ALP. For example, birth control pills may reduce their levels, while antiepileptic drugs may increase their levels.

● Patient Readiness:
Nighttime fasting is better, but not necessary for this test. Only drinking water is allowed.
This test usually does not require prior preparation.