Liver Blood Tests
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- What are the basic functions of the liver?
- What are common liver blood tests?
- What are the aminotransferases?
- Normally, where are the aminotransferases?
- What are normal levels of AST and ALT?
- What do high (elevated) liver tests (AST and ALT) mean?
- Do AST and ALT test results indicate liver function?
- What blood tests are done to detect liver function?
- What blood tests are done to detect liver function? (Continued)
- What are some common reasons for abnormal liver tests?
- What medications can cause increased liver enzyme tests (abnormal aminotransferase levels)?
- What medications can cause increased liver enzyme tests (abnormal aminotransferase levels)? (continued)
- What conditions can cause very high aminotransferase levels?
- What are some of the less common causes of elevated liver blood tests?
- What are some of the less common causes of elevated liver blood tests? (continued)
- How are healthy people evaluated for mild to moderate rises in aminotransferase levels?
- How are healthy people evaluated for mild to moderate rises in aminotransferase levels? (continued)
- How about monitoring liver blood tests?
- What about the other liver enzymes?
What are some common reasons for abnormal liver tests?
Abnormal liver tests may be detected in the blood in a variety of liver conditions.
- Mild to moderate elevations of the liver enzymes are common. They are often unexpectedly encountered on routine blood screening tests in otherwise healthy individuals. The AST and ALT readings in such cases are usually between twice the upper limits of normal and several hundred units/liter. One of the most common causes of mild to moderate elevations of these liver tests is a condition referred to as fatty liver (steatohepatitis or hepatic steatosis). In the United States, the most frequent cause of fatty liver is alcohol abuse. Other causes of fatty liver include diabetes mellitus and obesity.
- Chronic hepatitis B and hepatitis C are other causes of chronic mild to moderate liver enzyme elevation. In these conditions, ALT and AST may be only slightly high and the degree of abnormality in liver function tests can indicate the degree if injury.
- Chronic and acute alcohol use also can commonly cause abnormal liver blood tests. In alcoholic hepatitis, the range of liver tests can vary greatly. In chronic alcohol liver disease or alcoholic cirrhosis, slight elevation of ALT and AST may be observed, whereas in acute alcoholic hepatitis, high liver enzyme numbers are often seen.
- Many medications can be responsible for mild to moderate increase in the liver enzyme tests (see below).