In most cases, people only find out they have fatty liver when a routine blood sample shows there may be a problem. If this happens to you, your doctor may ask a lot of questions about your life-style, such any drugs you are taking (including over the counter medication and nutritional supplements) and the amount of alcohol you drink.
You may then be sent to see a liver specialist (hepatologist) or a digestive disease specialist (gastroenterologist) for further tests. Many of these tests will be used to rule out alcoholic liver disease, hepatitis B, hepatitis C, autoimmune hepatitis and other causes of liver disease.
Helping the doctors to help you
There is no specific laboratory test for NAFLD, making it difficult to diagnose. It is important that you answer questions about your lifestyle as accurately as you can. It is not easy for doctors to tell the difference between alcoholic liver disease and NAFLD so you will need to be honest about the amount of alcohol you drink.
Liver disease often shows few symptoms and doctors have to consider a number of conditions that could be affecting you. The better the picture of your general health you can provide, the better the chances will be that the doctors can pin down your illness.
Liver function tests
Tests should include liver function tests (LFTs) which are used to gain an idea of how the different parts of your liver are functioning. The liver function test is made up of a number of separate examinations, each looking at different properties of your blood. It is used to gain an indication of how much your liver is inflamed or damaged in its ability to work properly.
The test will measure levels of the liver enzymes ALT and AST which are increased during inflammation (hepatitis). In NAFLD, the doctors will expect to find ALT is higher than AST.
Test results are given in numbers and values. A laboratory provides a ‘normal value’ or ‘reference value’ to the test, which shows the doctor, nurse or specialist whether your test is
within the normal range. ‘Abnormal’ functions are shown by how much they are below or above the normal range. In biochemical tests associated with insulin resistance, abnormal results will include raised cholesterol, triglycerides and blood sugar (glucose).
Scanning your liver with imaging equipment such as ultrasound, computerised tomography (CT) or magnetic resonance imaging (MRI) may reveal significant deposits of fat in your liver.
Doctors may use a liver biopsy to assist or confirm their diagnosis. During a liver biopsy a tiny piece of the liver is taken for study. To do this, a fine hollow needle is passed through the skin into the liver and a small sample of tissue is withdrawn.
Abnormal liver function test results
Do not be alarmed by an ‘abnormal’ liver function test result. Strange as it sounds, abnormal LFTs are not uncommon. In some people results may often fall out outside normal range and doctors may consider that increases or decreases of certain substances in your blood are not an indication of serious liver disease.
However, the British Liver Trust encourages all people with any form of liver disease to take an active interest in their health care. The need to reduce unnecessary testing for those at low risk of disease should not restrict you from asking for further information from medical staff if you feel there is no follow-up to your abnormal LFT results.