High Alkaline Phosphatase (ALP) indicates liver or bone disorder. To confirm where the ALP is coming from, your physician may order a Bilirubin test, Aspartate Aminotransferase (AST) test and Alanine Amino transferase test to check liver function. If these tests are normal that means the problem is not in the liver but in your bones. You might be suffering from Paget’s Disease. However, if liver function tests are abnormal then high ALP indicates cirrhosis, mononucleosis, blocked bile duct and hepatitis. Low Alkaline Phosphatase (ALP) indicates Hypophosphatasia. It is a very rare congenital metabolic error which is characterized by abnormal bones and teeth. Hypophosphatasia occurs 1/300,000 and is usually associated with malnutrition or deficiency of zinc.