Elevated alkaline phosphatase occurs when levels of alkaline phosphatase (ALP) exceed the reference range. This group of enzymes has a low substrate specificity and catalyzes the hydrolysis of phosphate esters in a basic environment. The major function of alkaline phosphatase is transporting chemicals across cell membranes. Alkaline phosphatases are present in many human tissues, including bone, intestine, kidney, liver, placenta and white blood cells. Damage to these tissues causes the release of ALP into the bloodstream. Elevated levels can be detected through a blood test. Elevated alkaline phosphate is associated with certain medical conditions or syndromes (e.g., hyperphosphatasia with mental retardation syndrome, HPMRS). It serves as a significant indicator for certain medical conditions, diseases and syndromes. If the cause for alkaline phosphatase elevation is unknown, isoenzyme studies using electrophoresis can confirm the source of the ALP. Heat stability also distinguishes bone and liver isoenzymes ("bone burns, liver lasts"). It is essential to use age-specific normal reference values, as healthy infants and children usually have levels that would be considered elevated in adults. Causes Liver Liver (liver ALP): Cholestasis, cholecystitis, cholangitis, cirrhosis, primary biliary cholangitis, primary sclerosis cholangitis, fatty liver, sarcoidosis, liver tumor, liver metastases, drug intoxication Drugs: e.g. verapamil, carbamazepine, phenytoin, erythromycin, allopurinol, ranitidine, chlorpropamide, numerous antibiotics Bones Bone disease (bone ALP): Paget's disease, osteosarcoma, bone metastases of prostatic cancer (High / very high ALP values) Other bone metastases Renal osteodystrophy Fractured bone Skeletal involvement of other primary diseases: Osteomalacia, rickets, vitamin D deficiency (moderate rise) Malignant tumors (ALP originating from tumor) Renal disease (secondary hyperparathyroidism) Hyperthyroidism. Other unlisted musculoskeletal conditions may also cause elevated alkaline phosphatase. Obesity Elevated levels of the alkaline phosphatase enzyme are reported among those who have obesity. A study reported there were higher serum levels of alkaline phosphatase in obese than in the non-obese. With elevated alkaline phosphatase levels, there is an increase in disproportionate intracellular fat depots and thereby releasing itself into the bloodstream. The nature of the relationship between alkaline phosphatase and obesity is still being investigated. Kidney Elevated serum levels of alkaline phosphatase has been associated with chronic kidney disease (CKD). Studies have shown that elevated levels may predict mortality independent of bone metabolism factors and liver function tests in CKD. Elevated levels are also associated with diabetes, hypertension, and cardiovascular disease; it was found that elevated levels are associated with elevated serum C-reactive protein (CRP), which could reflect an inflammatory and