An ALT (alanine aminotransferase) sample measures the amount of this enzyme in the blood. ALT is normally found in red blood cells, the liver, heart, muscle tissues, pancreas and kidneys. ALT is found in liver cells and, in small quantities, in the blood. Unlike AST, ALT is only found in the cytoplasm of liver cells, so the level may be lower in the event of liver damage than when ASAT is sampled. Viral hepatitis causes very high ALT levels. The amount of ALT in the blood is halved in 36 hours. The ALT test can be carried out at the same time as a test for aspartate aminotransferase (AST). The ratio of AST to ALT can help to determine whether the liver or any other organ has been damaged and whether alcohol abuse has been one cause of the damage to the liver.
The ALT test is carried out in order to check the condition of the liver and see whether it has been damaged. This test makes it possible to identify liver diseases, in particular hepatitis and cirrhosis caused by alcohol, drugs or viruses. Liver diseases may cause symptoms such as pain in the upper part of the abdomen, nausea, vomiting and – sometimes – jaundice. Other reasons may include finding out whether jaundice was caused by a blood disease or liver disease, or keeping track of the effects of cholesterol-lowering medications and other medications that may harm the liver.
High levels seen in cases of acute and chronic hepatitis, toxic liver damage, mononucleosis and biliary obstruction. Many dietary supplements and medications. - Liver damage resulting from diseases. - Lead poisoning. - Rapid growth, particularly in small children, may cause slightly elevated levels of ALT.