Because most people with NAFLD have no symptoms and screening for it is not recommended at this time, fatty liver disease is often discovered during a routine blood test or screening for another medical condition. For example, your blood work may show high levels of liver enzymes, or an ultrasound of your abdomen might reveal that your liver looks enlarged. Your doctor will use a variety of methods to determine if you have fatty liver disease.
As part of the medical history, your doctor will ask:
During the physical exam, you doctor will:
If you have more or less muscle than is normal, your BMI may not be a perfect measure of how much body fat you have. Your healthcare provider may also take your waist circumference and waist-to-hip ratio into consideration.
The following blood tests will be included as part of your medical evaluation.
The cells in your liver contain proteins called enzymes, which are chemicals that help the liver do its work. When liver cells are damaged or destroyed, the enzymes in the cells leak out into the blood where they can be measured by blood tests. Liver enzyme testing usually checks the blood for two main enzymes:
If your liver is damaged due to inflammation, the level of these enzymes may be higher than normal. However, ALT and AST levels do not tell you how much scarring (fibrosis) may be present in your liver or predict how much liver damage will develop. In some people with NAFLD these liver enzymes may be normal as well
It’s likely other blood tests will be done to rule out co-existing causes for fatty liver, including:
Your doctor may order tests that take images, or pictures, of your liver to help make the diagnosis of liver disease. Different types of images can be obtained by using various types of equipment, including:
These tests cannot show inflammation or fibrosis, so your doctor can’t use them to determine whether you have simple fatty liver or NASH. However, there are other types of imaging tests that are used to measure fibrosis by measuring the stiffness of your liver. Liver stiffness indicates scarring; the more scarring that is present the stiffer your liver is. The following tests can help your doctor determine if, and to what extent, you have fibrosis of the liver.
If your medical evaluation shows no alternative causes for liver disease (such as medications, viral hepatitis, or excessive use of alcohol) and imaging studies of your liver show fat and liver stiffness, NASH is suspected. If your doctor feels that further confirmation is needed to make a definitive diagnosis of NASH, a liver biopsy may be ordered.
During a biopsy, your doctor will insert a needle between your ribs into your liver to collect a small sample of liver tissue for laboratory testing. 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. You can read more detailed information about preparing for a liver biopsy here.
Please call our helpline at 1-800-GO-LIVER if you have questions after speaking with your healthcare professional.
Ask your doctor to explain all your test results and their implications, and don’t hesitate to ask questions. This will help you have a better understanding of your diagnosis and why your healthcare provider is recommending a particular course of treatment going forward.
Last updated on November 1st, 2023 at 11:08 am