Alkaline phosphatase is an enzyme synthesized in the epithelial cells of the bile ducts in the liver, bones and osteoblasts, placenta, small intestines, kidney and spleen. In fact, it is an important part of metabolism.
It is an enzyme found in almost all plants and animals. It takes part in the processes of hydrolysis of phosphates and making them usable. ALP plays very important roles in bone formation, lipid metabolism and transport of metabolites.
It has around 60 similar isoenzymes. According to the heat resistance of these isoenzymes, they can be separated by electrophoresis, electrophoresis speed and heat resistance. In electrophoresis, in order of speed, liver, bone, intestines and placental ALP enzymes are the slowest. The order of heat resistance is like this. By detecting these sub-isoenzymes, it can be clarified where the high ALP level in the blood originates from.
During the damage of the cells in the area where it is located, ALP rises in a measurable area by going out of the cell in large amounts. In this case, in the case of high ALP, the source of the problem can be reached by starting from the determination of where ALP is produced or found.
Physiologically and naturally, ALP can be elevated especially in the third trimester of pregnancy, from placental origin, or from bone origin in children of developmental age.
ALP is found in the liver, bone, intestine, and placenta. For this reason, it is mostly used in the diagnosis and follow-up of liver, small intestine and bone diseases.
The normal value of alkaline phosphatase in the blood is 30-120 U/L. When evaluating liver function tests such as ALP, the patient’s past history is the main guide. However, the detected symptoms and other examinations of the patient should be evaluated together. Some patients may also need imaging modalities such as USG, CT or ERCP.
The most common possible causes of high ALP are:
- Causes originating from the liver and biliary tract
- Cholestasis
- Bile duct blockages
- Primary biliary cirrhosis
- Primary sclerosing cholangitis
- Infiltrative diseases of the liver
- Liver metastases
- Hepatitis
- Cirrhosis
- Bile duct absence syndrome
- Benign recurrent cholestasis
- tumors
- Medicines
- Anabolic steroids
- Gold salt
- Allopurinol
- Imipramine
- Amoxicillin clavulanic acid
- Indinivir
- Captopril
- Iprindole
- Carbamazepine
- Nevirapine
- Chlorpropamide
- Methyltestosterone
- Cyproheptadine
- Methylenedioxymethamphetamine
- Diltiazem
- Oxaprozin
- Erythromycin
- Pizotyline
- Estrogens
- Quinidine
- Floxuridine
- tolbutamide
- Flucloxacillin
- Total parenteral hyperalimentation
- Fluphenazine
- Trimethoprim-sulfamethoxazole
- Infections
- Viral hepatitis
- Infectious mononucleosis
- Rickettsia infection
- Advanced bone metastasis (if it originates from the pancreas, isolated ALP increase is seen without ALT)
- Congestive heart failure (usually with AST – ALT increase),
- Hodgkin lymphoma
- Chronic renal failure
- Inflammatory bowel diseases
- Diabetes
- Hyperparathyroidism
- Bone diseases
- osteomalacia
- Paget’s disease
The most common possible causes of low ALP are:
- Hypomagnesemia (Magnesium is the most important activator of alkaline phosphatase. ALP levels may also decrease in magnesium deficiency.)
- Hypokalemia
- Protein deficiency
- Chemicals and drugs
- EDTA
- Cysteine
- Iodine
- Hydrogen sulfide (H2S)
- Mercury
- Sulphite
- Phenanthroline
- Ascorbic acid
- Glycine
- histidine
- L-phenyl alanine
- Orthophosphates
- Sodium arsenate
- Urea
- L-Leucine
- Zinc
- Bismuth
- Tetranitromethane