metabolic dysfunction–associated steatohepatitis (MASH), formerly known as nonalcoholic steatohepatitis (NASH)MASLD and MASH Screening and Diagnosis
An Expert Review of MASLD/MASH: Focus on Screening and Diagnosis

Released: December 21, 2023

Expiration: December 21, 2024

Arun B. Jesudian
Arun B. Jesudian, MD

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Key Takeaways
  • The progressive form of metabolic dysfunction–associated steatotic liver disease (MASLD) is metabolic dysfunction–associated steatohepatitis (MASH), which places patients at risk of developing liver fibrosis, cirrhosis, and liver-related complications.
  • Identification of MASLD often occurs incidentally, when at-risk patients are tested for liver enzymes or undergo abdominal imaging.
  • Patients with MASLD and type 2 diabetes warrant further workup for MASH and related fibrosis according to the American Association for the Study of Liver Diseases. 
  • Noninvasive liver fibrosis assessments include serum-based FIB-4 score or the AST-to-platelet ratio index and imaging via vibration-controlled transient elastography.


Metabolic dysfunction–associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD), is an increasingly common cause of chronic liver disease and cirrhosis. It falls within the broad category of steatotic liver disease, which includes all causes of increased liver fat, including alcohol-related liver disease. Those with hepatic steatosis and a cardiometabolic risk factors (elevated BMI or fasting glucose, hypertension, or abnormal serum lipids including triglycerides) in the absence of other causes of liver fat accumulation are appropriately diagnosed as having MASLD. The progressive form of MASLD is metabolic dysfunction–associated steatohepatitis (MASH), formerly known as nonalcoholic steatohepatitis (NASH). MASH places patients at risk of developing liver fibrosis, cirrhosis, and liver-related complications. In terms of epidemiology, approximately 25% of the global population are estimated to have MASLD, 3% to 5% are estimated to have MASH, and 1% to 2% are estimated to be at risk of MASH-related cirrhosis.

Screening and Diagnosis of MASLD
Despite its prevalence, MASLD is usually asymptomatic and therefore can be underdiagnosed. In fact, identification of MASLD often occurs incidentally, when at-risk patients are tested for liver enzymes or undergo abdominal imaging. When MASLD is suspected, evaluation for the presence of metabolic syndrome and associated conditions is indicated. Heavy alcohol consumption and other liver disease also should be excluded. Basic testing includes a liver panel and testing for other underlying liver disease, including viral hepatitis and autoimmune liver disease serologies. A liver ultrasound also should be obtained to evaluate for the radiographic presence of liver fat.

If a patient is diagnosed with MASLD, the next step should be to determine if they are at risk of MASH. Predictors of MASH and related fibrosis among those with MASLD include age older than 50 years, the presence of type 2 diabetes, and having a first-degree relative with MASH-related cirrhosis. Of these, the American Association for the Study of Liver Diseases specifically identifies patients with type 2 diabetes as warranting further workup. Because clinical outcomes in MASH are exclusively related to the degree of liver fibrosis or scarring, fibrosis assessment is essential to risk stratify affected individuals.

Liver biopsy, although the gold standard of determining the etiology of liver disease and the extent of liver fibrosis, is rarely used for this purpose given the cost and risk, as well as the existence of noninvasive fibrosis assessments. Noninvasive testing includes serum-based tests and specialized imaging. Simple lab-based scores such as the FIB-4 score or the AST-to-platelet ratio index are readily obtained via basic bloodwork and online calculators and are effective at excluding the presence of significant fibrosis.

In terms of imaging, vibration-controlled transient elastography is an increasingly available test that can be obtained within minutes by healthcare professionals in office settings. It measures liver stiffness as a surrogate for liver fibrosis. In addition, 2D shear wave elastography and magnetic resonance elastography are radiographic noninvasive fibrosis assessments that are extremely useful in evaluating for the presence of advanced fibrosis or cirrhosis. Sequential testing with >1 noninvasive test (eg, a lab-based test followed by elastography) can decrease the likelihood of an indeterminate fibrosis assessment.

Management of MASLD and MASH
The goal of MASLD and MASH treatment is, ideally, resolution of MASH and reversal of liver fibrosis. The mainstay of treatment for MASLD continues to be lifestyle modification including aerobic and resistance exercise and diet modification. Weight loss is clearly associated with improved outcomes in MASLD and MASH, with more weight loss being required as the severity of disease progresses. When weight loss through lifestyle modification is difficult to achieve, bariatric procedures can be considered. Although there are no currently available medical therapies for MASH, several are in clinical development, and approved medications for weight loss, such as GLP-1 receptor agonists, may be effective in treating MASH.

Your Thoughts?
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