Alkaline phosphatase or ALP is an enzyme found in the liver. Like all enzymes, it functions as a catalyst. Chemically, it removes phosphate groups from many different molecules, among them nucleotides and proteins. As such, ALP has many important bodily functions involving metabolism of proteins and digestion. It operates best in an alkaline environment, as the name implies.
It is found in bacteria in the space outside the cell membrane. Because of the presence of phosphate groups in DNA, alkaline phosphatase is commonly used in molecular biology laboratories as a tool of biological research. Using the enzyme to remove the phosphate groups in experimental DNA can control certain chemical processes and facilitates radio labeling of the DNA samples.
Use In Testing
Alkaline phosphatase also has important uses in medicine, particularly diagnostic testing to reveal elevated or low ALP in the blood as a sign of liver disease and various other conditions. Alkaline phosphatase can be found in all human bodily tissues. It’s especially concentrated in the liver, however, and also in the bile ducts, kidneys, skeletal system, and the placenta during pregnancy. Alkaline phosphatase is one of the primary diagnostic enzymes for use in detecting liver disease and some other medical problems.
Normal Level
The normal levels of serum ALP in adult human beings is between 20 and 140 IU per liter. Levels of alkaline phosphatase are significantly higher than this in children and in pregnant women, however, without indicating any problems. Elevated ALP also has some causes that are skeletally related, such as in certain bone diseases that involve higher than normal levels of bone growth. The most prevalent use of a blood
test for serum alkaline phosphatase is however the early detection of liver disease.
Elevated Alk Phos
High levels of ALP in the blood can indicate a wide variety of liver diseases and problems with the bile system, making this blood test one of the first steps in diagnosis, and requiring follow-
can cause elevated ALP. So can intoxication with a number of drugs and also side effects of a number of medications, most commonly the statin class of drugs commonly used to treat high cholesterol.
Because elevated ALP can indicate such a large number of completely different liver diseases as well as non-
Medical imaging can be used to look for visible problems in the liver itself. Fatty liver disease appears in ultrasound, MRI, and other medical imaging as deposits of fatty tissue in the liver. Hepatitis (swollen or enlarged liver) is also revealed in medical imaging. Fibrosis and cirrhosis of the liver show up as scarring and fibrous growths within the organ. A liver biopsy, which involves taking a sample of liver tissue using a
needle inserted directly into the organ, can be used to diagnose liver cancer, infectious hepatitis, and certain other liver diseases.
Finally, all of this needs to be correlated with the patient’s lifestyle and other factors to determine what the probable cause is of any liver disease that is diagnosed, as the treatment of liver disease is usually a matter of treating the underlying causes. Alcohol abuse is probably the single most common and potentially serious cause of liver disease of nearly every kind (although it isn’t known to have any relation to liver cancer). Other causes of liver disease include obesity, diabetes, viral infections, and a large number of less common problems. Treatment of these lifestyle and medical problems can usually reverse or arrest the progress of liver disease that has not reached a late stage of liver dysfunction requiring a liver transplant. Continued monitoring of ALP and other liver enzyme levels is part of ongoing treatment.
Low Levels Of ALP
Lower than normal levels of ALP can also show up in diagnostic tests. There are a great many causes of this syndrome as well, generally having nothing to do with liver disease. Low ALP can result from estrogen replacement therapy given to postmenopausal women or as a treatment for osteoporosis. It can be a sign of severe anemia from various causes, including heart surgery and malnutrition.