Fatty Liver Disease (Nonalcoholic Steatohepatitis): Tests
A common liver disease, often without symptoms, that resembles alcoholic liver disease but occurs in people who drink little or no alcohol. The major characteristic of NASH is fat in the liver, along with inflammation and damage. NASH can be a complication of insulin resistance and diabetes.
About Fatty Liver Disease Tests
NASH is usually first suspected in a person who is found to have elevations in liver tests that are included in routine blood test panels, such as alanine aminotransferase (ALT) or aspartate aminotransferase (AST).
When further evaluation shows no apparent reason for liver disease (such as medications, viral hepatitis, or excessive use of alcohol) and when x rays or imaging studies of the liver show fat, NASH is suspected. The only means of proving a diagnosis of NASH and separating it from simple fatty liver is a liver biopsy.
For a liver biopsy, a needle is inserted through the skin to remove a small piece of the liver. NASH is diagnosed when examination of the tissue with a microscope shows fat along with inflammation and damage to liver cells. If the tissue shows fat without inflammation and damage, simple fatty liver or NAFLD is diagnosed.
An important piece of information learned from the biopsy is whether scar tissue has developed in the liver. Currently, no blood tests or scans can reliably provide this information. NIH – National Institute of Diabetes and Digestive and Kidney Diseases