Alkaline phosphatase, or ALP, is a protein found in all your body tissues. Your liver and bones contain significantly higher amounts. It exists in many forms, each type with a different chemical structure, called an isoenzyme. Its structure depends on where it is produced in your body. Your doctor can perform and interpret an ALP test to determine what your results mean.
Results
The normal value of ALP ranges from 20 to 140 IU/L. Normal ranges vary slightly depending on the laboratory, but your doctor can explain what your values mean. Adults have lower levels of ALP than children because growing bones produce higher levels of ALP. During rapid growth, it is not uncommon for levels to be as high as 500 IU/L. For this reason, children are primarily exempt from ALP testing. Abnormal results refer exclusively to adults.
Lower Than Normal
If your ALP results are lower than normal, it may indicate a protein deficiency. It may also mean you have a deficiency of magnesium -- a mineral utilized by every organ in your body, especially your heart, muscles and kidneys. Excessive vitamin D can also cause low ALP. Vitamin D promotes calcium absorption and regulates phosphate for bone growth. Other causes of low ALP test results are malnutrition and low vitamin C -- a nutrient needed for normal growth and development.
Considerations
An ALP test is performed to diagnose liver or bone disease and to determine if treatments are effective if you already have liver or bone disease. According to Medline Plus, the ALP tests is about 80 percent accurate for identifying specific locations of cancers and disease. However, it is not a completely reliable screening test because levels can be out of normal range for unknown reasons and return to normal. If levels are lower than normal, more investigation is necessary before diagnosing disease, especially if there are no other signs of disease.
Getting Accurate Results
Several medicines affect ALP levels, so it is important to prepare properly for the test in order to receive the most accurate results. Also, you should not eat or drink anything 10 to 12 hours before the test. Medicines that effect ALP levels include antibiotics, anti-inflammatory drugs, birth control pills, tranquilizers, certain arthritis drugs, some diabetes medicines, cortisone and narcotic pain medication. If you are prescribed medications that affect your blood ALP levels, consult your doctor about the best course of action. It is important that you do not stop taking prescribed medication without consulting your doctor.
