Key Facts About the MASLD Nomenclature Change
Your diagnosis is still valid
AASLD + EASL + ALEH co-led
For MASLD diagnosis (plus liver fat)
MASLD, MetALD, ALD, specific, cryptogenic
In 2023, the global liver disease community agreed to retire the term nonalcoholic fatty liver disease (NAFLD) and replace it with metabolic dysfunction-associated steatotic liver disease (MASLD). This AASLD special article explains what the change means in practice, how MASLD is defined, and how existing clinical guidance applies under the new terminology.
This was not a minor editorial revision, it was the result of a 56-country Delphi consensus process co-led by AASLD, EASL, and ALEH, designed to address three core problems with the old terminology: its exclusionary definition, its failure to name the metabolic root cause, and its use of language many patients found stigmatizing. ref 1 ref 2
The New Names Explained
The Delphi panel chose steatotic liver disease (SLD) as the new overarching term for all conditions involving hepatic fat accumulation, regardless of cause. The word "steatosis" replaces "fatty" because the latter was considered stigmatizing. ref 3 Within that umbrella, here is how every familiar term maps to its replacement:
| Old Term | New Term | Full Name |
|---|---|---|
| NAFLD | MASLD | Metabolic dysfunction-associated steatotic liver disease |
| NASH | MASH | Metabolic dysfunction-associated steatohepatitis |
| NAFL | MASL | Metabolic dysfunction-associated steatotic liver (no steatohepatitis) |
| NAFLD/NASH cirrhosis | MASLD/MASH cirrhosis | — |
| at-risk NASH | at-risk MASH | MASH with NAS ≥4 and fibrosis stage ≥2 ref 37 |
The histologic definition of steatohepatitis is unchanged, MASH is the same disease as NASH at the tissue level. ref 4 In clinical settings where biopsy is not performed, MASL can be inferred when non-invasive tests suggest the absence of steatohepatitis, though this requires further biomarker validation. ref 19
How MASLD Is Defined
MASLD requires three things: (1) hepatic steatosis detected by imaging or histology, (2) at least one cardiometabolic risk factor (CMRF), and (3) no other identifiable cause of steatosis. ref 5 The CMRFs are drawn from well-established cardiovascular disease criteria, adjusted for ethnicity. ref 6 Only one criterion is needed.
Cardiometabolic Risk Factors (Any 1 of 5 Required)
| # | Risk Factor | Qualifying Threshold |
|---|---|---|
| 1 | Obesity / Central adiposity | BMI ≥25 kg/m² (≥23 kg/m² Asian) or WC >94 cm (M) / 80 cm (F) ref 7 |
| 2 | Dysglycemia / Diabetes | Fasting glucose ≥5.6 mmol/L or HbA1c ≥5.7% or T2DM or T2DM treatment ref 8 |
| 3 | Hypertension | BP ≥130/85 mmHg or antihypertensive treatment ref 9 |
| 4 | Elevated triglycerides | Triglycerides ≥1.70 mmol/L [150 mg/dL] or lipid-lowering treatment ref 10 |
| 5 | Low HDL-cholesterol | HDL ≤1.0 mmol/L [40 mg/dL] (M) or ≤1.3 mmol/L [50 mg/dL] (F) or lipid-lowering treatment ref 11 |
The Full SLD Classification System
SLD (steatotic liver disease) is now the umbrella term for all liver fat conditions. It has five subcategories, each driven by a different primary cause. ref 3 Multiple causes can coexist; for example, MASLD can occur alongside autoimmune hepatitis, and the new nomenclature explicitly allows this dual diagnosis. ref 41
MASLD
Liver fat plus at least one of the five CMRFs above, with no other identifiable cause. This is the most common category and covers nearly all of what was previously called NAFLD. ref 5
MetALD: The New Overlap Category
MetALD (metabolic dysfunction and alcohol-associated steatotic liver disease) is a new category for patients who meet MASLD criteria but also drink alcohol above the safe threshold. Specifically: between 20-50 g/day for females and 30-60 g/day for males (weekly equivalents: 140-350 g and 210-420 g respectively). ref 21 MASLD itself requires alcohol consumption below 20 g/day (females) or 30 g/day (males). ref 20
Delphi panelists were nearly unanimous that this level of combined metabolic and alcohol exposure alters disease natural history (95% agreement) and may reduce response to treatment (90% agreement). ref 22 MetALD patients are considered at risk for faster disease progression than MASLD alone. ref 23
| Category | Females (daily) | Males (daily) |
|---|---|---|
| MASLD | <20 g/day | <30 g/day |
| MetALD | 20-50 g/day | 30-60 g/day |
| ALD | >50 g/day ref 43 | >60 g/day ref 43 |
Specific Etiology SLD and Cryptogenic SLD
When steatosis has a distinct identifiable cause other than metabolic risk, the patient falls into "specific etiology SLD." This includes drug-induced liver injury, Wilson disease, lysosomal acid lipase deficiency, HCV genotype 3 infection, malnutrition, celiac disease, HIV, and certain environmental toxins. ref 24 When no cause can be found and no CMRFs are present, the patient is classified as having "cryptogenic SLD" and should be monitored periodically for the future emergence of CMRFs. ref 25
The Evaluation Algorithm
AASLD recommends a tiered approach to risk stratification that begins in primary care and escalates to gastroenterology/hepatology as needed. The algorithm is unchanged by the nomenclature update. ref 26
Step 1: Primary Risk Assessment with FIB-4
In primary care or any low-prevalence setting, the initial goal is to exclude advanced fibrosis using a test with high negative predictive value. FIB-4 is recommended as the first-line tool. ref 28 Important cutoff notes:
| FIB-4 Result | Action |
|---|---|
| <1.3 (general adults) <2.0 if age >65 ref 31 |
Follow in primary care. Reassess every 2-3 years if no T2DM and <2 metabolic risks. ref 29 Reassess every 1-2 years if T2DM or ≥2 metabolic risks. ref 30 |
| 1.3 - 2.67 | Secondary assessment with VCTE (FibroScan) or ELF preferred. ref 33 |
| >2.67 | Consider direct referral to gastroenterology/hepatology for further evaluation. ref 33 |
FIB-4 has important age limitations: it has reduced accuracy in patients under age 35 (consider secondary testing if metabolic risk or elevated liver enzymes are present) ref 32, and the cutoff shifts upward to >2.0 in patients over age 65. ref 31
Step 2: Secondary Risk Stratification with VCTE or ELF
When FIB-4 is ≥1.3, secondary testing with VCTE (FibroScan) or ELF refines the fibrosis risk level. In higher-prevalence settings such as hepatology clinics, MRE may be used when NITs are indeterminate. ref 34
| Risk Level | VCTE (FibroScan) | ELF Score | Suggested Action |
|---|---|---|---|
| Low | <8.0 kPa | <7.7 | Primary care follow-up or reassess |
| Intermediate | 8-12 kPa | 7.7-9.8 | Specialist referral; consider biopsy |
| High | >12 kPa | >9.8 | Gastroenterology/hepatology |
A special note: in patients with confirmed or suspected advanced fibrosis, an ELF score ≥11.3 is an FDA-cleared predictor of future liver-related events. ref 35
When to Consider Liver Biopsy
Biopsy is still recommended when: NITs suggest fibrosis ≥F2 and at-risk MASH is suspected (using tools like FAST, MEFIB, MAST, or corrected T1); NIT results are indeterminate; liver enzymes have been persistently elevated for more than 6 months; or additional/alternate diagnoses are possible. ref 36 At-risk MASH is defined as MASH with a NAFLD activity score (NAS) ≥4 and fibrosis stage ≥2 - the subgroup most likely to benefit from pharmacotherapy. ref 37
What Hasn’t Changed: Clinical Practice Impact
The most important practical message of this guidance is simple: every recommendation in the 2023 AASLD NAFLD Practice Guidance on clinical assessment and management applies directly to MASLD patients. ref 26 This includes risk stratification algorithms, treatment thresholds, monitoring recommendations, and the approach to comorbidities.
The only substantive addition to the guidance is the new MetALD category. Previously, patients with NAFLD who drank more than mild amounts of alcohol were classified as NAFLD + alcohol. Under the new system, they are separately classified as MetALD, which should prompt clinicians to address both the metabolic and alcohol components of their care. ref 27
Multidisciplinary Care Remains the Goal
AASLD emphasizes that optimal management of MASLD requires a team of specialists, not just a hepatologist. ref 38 The recommended team typically includes primary care (for metabolic comorbidities and FIB-4 screening), gastroenterology/hepatology (for comprehensive fibrosis staging, liver-directed therapy, and clinical trial access) ref 39, nutrition and lifestyle specialists, health psychology, and cardiology or weight management specialists where needed. All patients should have a dietary/nutritional assessment and a structured follow-up plan independent of whether they are seeing a liver specialist. ref 40
The overlap data is reassuring from a research standpoint as well: the diagnostic accuracy of FibroScan (VCTE) and FIB-4 for stratifying patients by fibrosis risk was essentially identical whether the population was defined as NAFLD or MASLD. ref 18 Decades of clinical research into NAFLD and NASH: natural history studies, biomarker validation, and treatment trials, remain fully applicable to MASLD and MASH patients. ref 18