Nonalcoholic steatohepatitis, or NASH, is a serious liver condition on the rise around the world. NASH is the more severe form of nonalcoholic fatty liver disease (NAFLD). It can lead to inflammation, scarring, and liver damage if left untreated.1
Healthcare providers often use a combination of diagnostic tests and methods to reach a NASH diagnosis. These methods also help them determine how severe NASH is. Early detection allows for timely treatment, which is critical for both NASH and NAFLD.2
Physical exam and medical history
A thorough physical exam by a healthcare provider is the first part of a NASH diagnosis. Your doctor may check for signs of an enlarged liver or any tenderness in your stomach area.2
Your doctor will also go over your medical history. They will ask about any comorbidities that may put you at increased risk for NASH, such as:2
- Being overweight or having obesity
- Type 2 diabetes
- High levels of cholesterol and triglycerides (fats) in your blood
- Hepatitis C
- Cardiovascular disease (CVD)
Your doctor will also discuss your diet and lifestyle habits. They may ask what you typically eat, how much physical activity you get, and whether you smoke or drink alcohol. People who do not exercise, eat a poorly balanced diet, and consume a lot of sugar have a higher risk of developing NASH.2
Body mass index (BMI)
Body mass index uses your height and weight to measure whether you are overweight or have obesity. BMI plays a key role in a NASH diagnosis. This is because people with higher body weights have an increased risk of developing NASH.2
Blood work and liver function tests
Blood tests are crucial for evaluating liver function and overall liver health. Liver function tests measure the levels of enzymes and proteins in your blood. These levels may suggest liver inflammation or damage.2
Fibrosis-4 (Fib-4) calculator
The Fibrosis-4 (Fib-4) calculator is a noninvasive tool used to estimate the degree of liver scarring (fibrosis). Fibrosis is a key indicator of liver damage. It can help your doctor estimate the progression of liver disease.2,3
The Fib-4 calculator uses the following information to arrive at a score:3
- Age
- AST (aspartate aminotransferase) – A liver enzyme that, when elevated, can indicate liver damage.
- ALT (alanine aminotransferase) – Another liver enzyme that is elevated in people with liver disease.
- Platelet count – Platelets are blood cells involved in clotting. Abnormal platelet levels can suggest liver problems.
This information is put into a formula, which then calculates a score. The higher the score, the higher a person’s risk of fibrosis.2,3
The Fib-4 calculator helps healthcare providers identify which people might need additional tests, such as imaging or a liver biopsy.2
Imaging tests
Imaging tests provide detailed pictures of the inside of the body. This technology helps doctors assess the liver’s size and texture. It also helps them see whether there are any fatty deposits or signs of inflammation. These tests are noninvasive and can help rule out other liver conditions.2
Some imaging tests that your doctor might use to assess your liver health are:2,4
- Ultrasound
- Computed tomography (CT) scan
- Magnetic resonance imaging (MRI)
Elastography
An elastography is a newer type of imaging technique. It uses specialized ultrasound to measure liver stiffness. This test helps your doctor see fibrosis. It is a quick, painless procedure that offers valuable information about liver health and any damage. Different types of elastography include:2,4
- Vibration-controlled transient elastography
- Shear wave elastography
- Magnetic resonance elastography
Liver biopsy
In some cases, a liver biopsy may be necessary. A liver biopsy remains the gold standard in diagnosing NASH. It is the only test that can confirm whether you have NASH. It also can detect fibrosis at earlier stages than elastography can.2,4,5
During a biopsy procedure, a small sample of liver tissue is removed. A pathologist then studies the tissue under a microscope. Pathologists are healthcare professionals who specialize in diagnosing diseases. The pathologist will look for inflammation, fatty tissue, and fibrosis. Biopsies provide detailed information, but they are more invasive than other tests.2,4,5
Several types of liver biopsy may be performed, including:2,5
- Percutaneous liver biopsy – A thin needle is inserted through the skin and into the liver to remove a small sample of liver tissue.
- Transjugular liver biopsy – A needle is inserted through a vein in the neck (jugular vein) and guided into the liver with imaging to remove the sample.
- Surgical liver biopsy – A small incision in the abdomen is made to directly access the liver and remove a tissue sample. This method is less commonly used than the other methods because it is slightly more invasive.
Early detection is key
NASH is known as a “silent disease,” meaning symptoms often go unnoticed in the early stages. But the longer symptoms go unnoticed, the more damage the liver endures. Detecting NASH early can greatly improve overall liver health and disease prognosis. The main goal in treating NASH is to prevent the disease from getting worse and reduce the risk of health complications.6
Talk to your doctor
If you are concerned about your risk level for NASH, talk to your doctor. Tell your doctor if you have certain comorbidities that put you at increased risk for NASH, including obesity, CVD, or type 2 diabetes. Remember, NASH symptoms slowly develop over time. Staying on top of your liver health is crucial, especially if you have other underlying medical issues.6