Alkaline phosphatase is a group of enzymes found throughout your body in your tissues. Your liver and bones contain particularly high ALP amounts. Your kidneys and intestines contain ALP in smaller amounts. ALP levels are generally used as a marker for liver function. ALP measurement also helps detect bone disease. If your ALP test is out of the normal range, discuss your results with your doctor.
Function
ALP's functional importance is not well understood. However, according to a study conducted by the Department of Pharmacokinetics and Drug Delivery at the University of Groningen in the Netherlands and published in 1997 in the journal "Laboratory Investigation," clinical data from animal research suggests that one of the functions of ALP is to help protect against endotoxins -- bacteria that your immune cells can recognize.
Normal Range
The normal range for ALP is 44 to 147 IU/L. However, ranges vary depending on the laboratory, so it is important to use the reference ranges from the laboratory that conducts your test. Normal ALP ranges also vary depending on your age and gender. Children experience growth spurts that increase ALP levels, which is considered normal. You doctor can analyze your results and determine whether or not you are within the normal range for your age and gender.
Bile Significance
Your gallbladder is a small organ connected to your liver that stores and releases bile -- a digestive substance. Bile helps break down fat from your diet. The cells that line the liver's bile system are the ALP source, so proper gallbladder function and bile flow are essential to maintaining normal ALP levels.
Abnormal Ranges
Having results that are above or below the normal range can indicate several things. Bile obstruction and gallbladder disease can increase ALP levels. Liver congestion and dysfunction can also increase ALP levels. Conditions and diseases that impair liver function such as hepatitis and mononucleosis are known to increase ALP levels. Other issues that increase ALP include bone disease and gastrointestinal disorders. Lower than normal ranges are not as alarming; however, nutrient deficiencies are commonly responsible, particularly vitamin B-6, zinc, folic acid and vitamin C deficiency.
