Alkaline phosphatase in the blood
What is alkaline phosphatase?
Alkaline phosphatase is a specific enzyme that belongs to the group of hydrolases. It is necessary in order for the body to successfully undergo dephosphorylation reactions, namely: the elimination of phosphate from organic substances, which occurs at the molecular level. Carrying phosphorus through the cell membrane, phosphatase has a certain constant concentration in the blood and is an indicator of the rate of phosphorus-calcium metabolism. The name "alkaline" enzyme is due to the fact that it exhibits the greatest activity in the presence of a pH of the medium in the range from 8.6 to 10.1.
Despite the fact that alkaline phosphatase is one of the most common enzymes, its mechanism of action has not been fully understood. It should be noted that in the human body it is present almost everywhere, in all tissues, but at the same time it is presented in several varieties: renal, intestinal, placental, hepatic and bone. As for blood serum, in adults, phosphatase is represented by the latter two isoenzymes, in relatively equal amounts. In the bones, the enzyme is formed in osteoblasts, and in the liver in hepatocytes. The higher the activity of certain cells, for example, with bone fractures or with the destruction of liver cells, the higher the level of phosphatase in the blood becomes.
The rate of alkaline phosphatase in the blood
As for the normal level of alkaline phosphatase in the blood, these readings fluctuate in fairly wide ranges, they can range from 44 to 147 IU / L. In this case, it is worth paying attention to the sex of the person from whom the blood was taken for research, as well as his age. In pregnant women, this indicator may be slightly overestimated, as well as in adolescents who are in puberty, but it will not indicate any abnormalities in their body. This is simply due to the restructuring of some life support systems, as well as the growth of bone tissue or placenta.
In addition, the indicators of the norm may vary depending on the reagents used for its study in different laboratories, since there is no standardized method at this point in time. Specific figures change, but the range of their fluctuations, nevertheless, remains insignificant, therefore, when determining the norm, one can rely on the following averaged indicators:
- for children under 10 years old - from 150 to 350
- for children from 10 to 19 - from 155 to 500
- for adults under the age of 50 - from 30 to 120
- for the age category from 50 to 75 - from 110 to 135
- for people over 75 years old - from 165 to 190
These reference values are based on international units per liter.
Alkaline phosphatase increased
The study of an increase or decrease in the level of phosphatase in the blood is carried out according to some indications. This can be preparation for surgical intervention, as well as a routine examination of the patient. They take blood to determine the level of this enzyme and during the "liver tests" to assess the functional capacity of the organ.
Often, when patients complain of fatigue, loss of appetite, nausea or pain in the right hypochondrium, the level of alkaline phosphatase in the blood is studied. An indicative result is also for the diagnosis of various lesions of bones and bone tissue.
When alkaline phosphatase is elevated, it almost always means either damage or involvement in some pathological process of either the bones, or the liver, or the biliary tract. Additional studies help to differentiate and clarify the results, so if, along with this enzyme, there is an overestimation of the level of ALT and AST, then this clearly indicates liver disease. If, in conjunction with alkaline phosphatase, the level of calcium and phosphorus is increased, then damage to the bone tissue is evident.
Reasons for an increase in alkaline phosphatase
As one or another reason, four main subgroups can be distinguished that lead to an increase in the level of this enzyme in the blood:
- The first group is disorders associated with changes or diseases of the liver. It can be obstructive jaundice, which is caused by obstruction of the bile ducts, stones located in the bile ducts, as well as the appearance of scars in them after operations. Cancer of either the head of the pancreas, or stomach, or liver with metastases. With hepatitis of any origin, an increase in phosphatase is observed, as well as with cirrhosis. Another viral infection, namely infectious mononucleosis, can cause liver dysfunction, and as a result of an increase in this enzyme in the blood.
- The second group is disorders associated with changes in bone tissue. This includes diseases such as osteomalacia (softening of bone tissue due to calcium deficiency), osteosarcoma, metastases affecting bone tissue, Paget's disease (abnormal growth of bones with changes in their structure), fractures, rickets, and myeloma.
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The third group includes other reasons. The jump in alkaline phosphatase levels may be associated with myocardial infarction, ulcerative colitis and bowel perforation, and hyperparathyroidism (a hormonal disease characterized by the leaching of calcium from the bones).
- The fourth group - these are conditions not associated with diseases, but due to a number of factors. This includes pregnancy, adolescence, healthy women under 20 and healthy men under 30, as well as taking antibiotics and hormonal drugs for contraception and a number of other medicines included in a rather extensive list containing up to 250 items. Also, if the blood has been cooled after it has been drawn for examination, the alkaline phosphatase level will be overestimated.
It should be noted that an increase in the level of this enzyme is not in all cases, without exception, an indicator of a particular disease. Sometimes it can exceed the norm even in absolutely healthy people. Therefore, in order to judge the presence of one or another pathological process, it is necessary to conduct additional research and study the results obtained in a complex.
Alkaline Phosphatase Decreased
You should pay attention to a decrease in this enzyme in the blood, since such an indicator can serve as signs of a number of diseases that are no less dangerous than when the level of phosphatase is increased.
Possible reasons that lead to a decrease in enzyme levels:
- Significant blood transfusion.
- Decreased functionality of the thyroid gland.
- Severe anemia.
- Lack of elements such as magnesium and zinc in the body.
- A rare disease, hypophosphatasia, is congenital and leads to the fact that bone tissue softens.
- In pregnant women, a decrease in alkaline phosphatase may be a sign of placental insufficiency.
So, in order to qualitatively assess the result of an increase or decrease in the level of alkaline phosphatase in the blood, any specialist will need additional research. It is worth remembering that the boundaries within which normal phosphatase values can be located are quite extensive and significantly depend on the age of the subject. Therefore, even a doctor cannot accurately diagnose the presence of this or that disease only with an increase in the level of this enzyme. However, this indicator, combined with additional research, can provide a complete picture of the disease.
Article author: Mochalov Pavel Alexandrovich | d. m. n. therapist
Education: Moscow Medical Institute. IM Sechenov, specialty - "General Medicine" in 1991, in 1993 "Occupational Diseases", in 1996 "Therapy".
