What does the liver do and what are elevated liver enzymes?

The liver is the body's largest internal organ. It is located below the diaphragm on the right side of the abdomen. The liver performs many functions, including the following:

  • Produces most of the proteins the body needs.
  • Metabolizes (breaks down) nutrients from food to produce energy.
  • Prevents shortages of nutrients by storing certain vitamins, minerals, and sugar.
  • Produces bile, a substance that helps digest fat and absorb vitamins A, D, E and K.
  • Produces substances that help with blood clotting.
  • Helps your body fight infection by removing bacteria from the blood.
  • Removes potentially poisonous byproducts of certain medications.

What are liver enzymes?

An enzyme is a chemical that accelerates (speeds up) chemical reactions within the body. There are several enzymes in the liver, including alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (GGT). Elevated liver enzymes, found with a blood test, indicate inflamed or injured liver cells.

Why does a doctor check for elevated liver enzymes?

A doctor may order a liver enzyme test if a patient is being treated for liver disease or has a higher risk for liver disease. For instance, if the liver is injured, ALT is released into the bloodstream, and levels of this enzyme would be elevated.

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