There is no simple test for metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known as non-alcoholic fatty liver disease, or NAFLD)non-alcoholic fatty liver disease (NAFLD).

Lab tests that show elevated liver enzymes (ALT and AST), indicating liver inflammation, may lead to further testing that reveals fat in the liver, but some people  with MASLD have normal liver enzyme levels. Other blood biomarkers may also suggest fatty liver disease.

Clinical signs and reported symptoms tend to be more evident when MASLD has progressed to metabolic dysfunction-associated steatohepatitis (MASH, formerly known as non-alcoholic steatohepatitis, or NASH).

Various imaging methods can show the presence of fat in the liver. Transient elastography (FibroScan), a type of ultrasound imaging, can reveal both fat accumulation and fibrosis (scar tissue in the liver).

A liver biopsy, in which a small sample of liver tissue is collected with a hollow needle and examined under a microscope, is considered the gold standard for diagnosing steatotic liver disease. Biopsies can reveal fat in liver cells, enlargement or “ballooning” of cells, fibrosis, inflammation and other liver damage. But this is an invasive test with a small risk of complications, and it is not suitable for routine screening.

Clinicians use a variety of methods to assess the likelihood of MASLD, fibrosis and cirrhosis based on combinations of blood biomarkers and demographic factors such as age. The development of more accurate noninvasive methods for diagnosing and monitoring fatty liver disease is an active area of research. 

Last Reviewed: November 13, 2023