Patient's question:
My baby is five and a half months old and doesn't like to drink milk. His complexion is slightly yellow. The liver function test results show Alanine Aminotransferase (ALT) at 58 and Aspartate Aminotransferase (AST) at 68. When he was two weeks old, he got diaper rash, and the doctor said his AST was high. I would like to ask for the normal range.What help do I need: What is the normal range for AST?
Doctor's answer:
The normal value of Alanine Aminotransferase (ALT) is 0-40 U/L. Liver transaminases can be broadly categorized into Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST), among others. ALT is primarily found in liver tissues, while AST is present in the heart and other tissues and organs. Since the total amount of transaminases in the liver is about 100 times that in the blood, if all released enzymes remain active, just 1% of liver cell damage is sufficient to double the enzyme activity in the serum. Additionally, due to the 1000 to 5000-fold higher concentration of transaminases within liver cells compared to serum, these enzymes can also leak into the blood due to this concentration gradient.There are many factors that can cause elevated ALT levels, such as: acute hepatitis, medication use (especially drugs that are harmful to the liver), long-term alcohol consumption or a single large dose of alcohol, as well as certain biliary diseases, heart failure during heart disease, fever, and other conditions. Simply having elevated transaminase levels (abnormal liver function) does not necessarily confirm hepatitis. To diagnose hepatitis, the following three conditions must be met simultaneously: symptoms and signs of hepatitis (e.g., low-grade fever, anorexia, nausea, vomiting, fatigue, poor appetite, liver enlargement, and pain), clinical diagnosis (e.g., acute jaundice, chronic persistent type), and serological transaminase elevation. Additionally, etiological diagnosis is required (e.g., positive for hepatitis A antibody indicates type A hepatitis; positive for hepatitis B surface antigen, e antigen, and core antibody indicates type B hepatitis).
In some cases, elevated transaminase levels alone may be due to interference from factors such as excessive alcohol consumption, intense exercise, working night shifts, colds, or oral medication use before the test.