Alkaline phosphatase (abbreviated as ALP) is a group ofhydrolase enzymes, present in the human body. There are several ALP isoenzymes,known as ALP1, ALP2 and ALP3. ALP1 is usually found in the liver, ALP2 in thehuman bone, placenta and kidneys, while ALP3 is mostly found in the lining ofthe intestines. These tissues all release ALP to the bloodstream. To work, thisenzyme need alkaline pH (around 10), and in that surrounding it is able to takea phosphorus group of certain molecules. The process is known asde-phosphorylation and it is performed on alkaloids, proteins and nucleotidesin the body.
The ALP blood tests are measuring the total amount of allALP isoenzymes in the body. Usually, they are done to diagnose some bone andliver diseases, or to establish the toxic effects of medications to the liver. Anotherreason to perform ALP test is to detect some other medical conditions, including:malnutrition, protein deficiency, alcoholism, liver cirrhosis, gallstones, kidneycarcinoma, endocrineoplasia (endocrine glands tumors), etc.
Normal ALP Levels
The level of ALP mainly depends on the age, but also on theactivity and stage of growth of bone cells (osteoblasts and osteoclasts). As normallevel of alkaline phosphatase, doctors consider the values between 50 and75mg/dl (milligrams per deciliter). Teenagers and young adults might normally haveslightly higher ALP levels than adults.
Everything over 75mg/dl is considered as high ALP level andit is not healthy, since it might indicate some bone, placental, intestinal orliver problems.
What Can Cause High ALP?
Many conditions and diseases could cause high level ofalkaline phosphatase in the blood. As we already said, it is normal foradolescents, but also for some pregnant women, to have slightly increased levelof blood ALP.
Bone diseases and cancers, especially Paget’s disease cancause high blood ALP and lead to bone deformities, pain and abnormal bone fractures.Liver cholestasis and congestion, obstruction of the biliary tracts,inflammation caused by medications or increased level of toxins in the livermight also cause elevated levels of ALP.
Other causes of high ALP include various conditions, suchas: virus and parasitic infections, gastrointestinal of systemic infections, congestiveheart failure myocardial and pulmonary infarctions, leukemia, sarcoidosis, amyloidosis,Hodgkin’s lymphoma, rheumatoid arthritis or obstructive pancreatitis, etc. Abnormalfunctioning of the glands in the human body might also provoke high level ofalkaline phosphatase in the blood. Over activity of the thyroid or parathyroidglands, or adrenal cortical hyperfunction can be some of the reasons for highALP. Different gynecologic malignancies or increased use of contraceptivetablets could also cause high level of alkaline phosphatase in the bloodstream.