Alkaline phosphatase (ALP) is the enzyme which is contained practically in all cells of our body, but its maximum quantity is in the bone tissue, liver cells, lining of intestines and placenta (during pregnancy). Its function consists in detachment of phosphoric acid from organic molecules, thereby taking part in phosphorus exchange.

Alkaline phosphatase level depends on many factors – sex, age, prevailing types of food. However, its increase points to pathological changes in certain organs of human body.

ALP is located on the surface of cells in the bone tissue that actively participates in the bone growth. That’s why there is a close relationship between ALP increase in the blood and diseases of bone tissue. Enzyme activity quickly increases during cancerous diseases of bones. 

ALP elevation due to hepatic disorders has 2 causes: first of all, during death of liver cells (hepatitis, cirrhosis, taking medicine that affects liver, alcohol) enzyme is withdrawn from destroyed cells; secondly, due to biliary obstructive disorder when bile outflow is disrupted because of stones, inflammation, parasites, tumour cells.

Normally ALP is withdrawn with bile through intestinal tract and since outflow is troubled then absorption of the substance in the blood occurs. ALP value is elevated among women with eclampsia (disease of pregnant women clinically reminding epileptic seizure) connected with injury of placenta. 

Decrease of activity among pregnant women tells about deficiency of placenta development. Besides above-mentioned causes activity of alkaline phosphatase is elevated during parathyroid gland diseases (secondary hyperparathyroidism), renal rickets, cytomegalovirus infection, inflammatory bowel disease.

 Decrease of enzyme is observed during vitamin C deficiency, deficient function of thyroid gland, severe anaemia and phosphorus deficiency in the body.