Alkaline phosphatase (AF)
Alkaline phosphatase (AF) is examined when there is a suspicion of problems with the liver or bile ducts. It is often determined together with ASAT, ALAT and Gamma-GT. The most important causes for an increase of alkaline phosphatase in the blood are disorders of the liver, the bile ducts or the skeleton.
Alkaline phosphatase (AF) is an enzyme that can remove phosphate groups from various molecules, such as nucleotides, proteins, etc. AF detectable in the blood is mainly from liver parenchyma, bile duct epithelium and osteoblasts. To a lesser extent, it is also produced by and intestinal epithelium, placenta and renal tissue.
With regard to bone diseases, it is often seen as a measure of osteoblast activity. Alkaline phosphatase is therefore requested in the diagnosis and follow-up of liver disease, bile duct problems and bone diseases.
If an elevated concentration of alkaline phosphatase is measured in addition to an elevated and gamma-glutamyltransferase, there may be liver disease, whereas an isolated alkaline phosphatase elevation may be a sign of bone disease, such as Paget's disease.
Increases in blood AF not associated with "disease" are seen during pregnancy and in the recovery phase after bone fractures.
Elevation may occur with liver abnormalities such as hepatitis, cirrhosis, or a space occupying process. Another important reason for elevation is an obstruction of the bile ducts, then bile cannot drain properly from the gallbladder. Fatty meals, pregnancy, or kidney failure can also play a role in elevated alkaline phosphatase giving.
Lowered alkaline phosphatase occurs in menopausal women taking estrogen for osteoporosis. But also in people with malnutrition, magnesium deficiency, anemia, a slow-working and thyroid gland or after a severe period of diarrhea.
Some medications can affect the outcome of determinations: for example, corticosteroids increase alkaline phosphatase.