No single test can accurately diagnose nonalcoholic steatohepatitis (NASH). Your doctor will ask about your medical history and do a physical exam along with a number of other tests to rule out other conditions that may be causing your symptoms. A diagnosis of NASH requires that you have:

• No history of significant alcohol intake (more than 1 to 2 drinks per day).
• No other liver diseases.
• Fat buildup in the cells of your liver.

Imaging tests can detect whether fat is building up in the cells of your liver, but they cannot show whether this has led to liver inflammation or scar tissue. They are used to rule out other causes of liver disease and to rule out liver tumors if cirrhosis is present. Imaging tests that may be done include:

• Abdominal ultrasound.
• CT scan.
• MRI scan.

A liver biopsy may be done to confirm a diagnosis of NASH. In a liver biopsy, a sample of tissue is taken from the liver and examined under a microscope for abnormal signs.