Fatty liver

Clinically: Metabolic dysfunction-associated steatotic liver disease · also fatty liver, NAFLD, MASLD, hepatic steatosis, liver fat

hepatic ICD-10 K76.0 MONDO MONDO:0004790 unverified

This describes what this condition typically looks like. It is not a diagnosis and cannot tell you whether you have it -- patterns overlap, results vary between labs, and the same numbers mean different things in different people. Diagnosis usually rests on Triglycerides, Hemoglobin A1c, HDL cholesterol, interpreted alongside symptoms and history rather than read off a report.

unverified These explanations are written to be easy to read and have not yet been checked against a source. The ranges and measurement notes on this page show theirs.

definition unverified

Fat has accumulated inside liver cells. In its early form it causes no symptoms at all and is very often found by accident on a routine blood test.

Hepatic steatosis, identified by imaging or histology, together with at least one of five cardiometabolic risk factors and no other discernible cause; it ranges from steatosis with little or no inflammation (MASL) to metabolic dysfunction-associated steatohepatitis (MASH), which can cause fibrosis and cirrhosis. Those who also drink 140-350 g/week (women) or 210-420 g/week (men) are classed separately as MetALD.

caveats unverified

Usually silent, and usually found through a mildly raised liver enzyme with no symptoms. The early stage is reversible, which is the main reason finding it matters. Blood tests suggest it; imaging is what actually shows it.

No clinical version written yet.

How common it is

The most common liver condition in many countries, affecting roughly a quarter of adults, and closely tied to weight and insulin resistance.

The typical lab pattern

What the diagnosis rests on

The results a diagnosis is actually made on.

Triglycerides	high	ref ≤ 150	One of the five cardiometabolic criteria (any one is enough, with fat in the liver): triglycerides 150 mg/dL or higher, or lipid-lowering treatment.
Hemoglobin A1c	high	ref ≤ 5.7	One of the five cardiometabolic criteria (any one is enough, with fat in the liver): HbA1c 5.7% or higher, fasting glucose 100 mg/dL or higher, or type 2 diabetes or its treatment.
HDL cholesterol	low	ref ≥ 40	One of the five cardiometabolic criteria (any one is enough, with fat in the liver): HDL 40 mg/dL or lower in men, 50 mg/dL or lower in women, or lipid-lowering treatment.

Consistent with it

Fits the picture, but not enough on its own.

Alanine aminotransferase	high	—	A raised ALT can make a doctor suspect it, but it is not part of the definition, and liver scarring can be present with normal enzymes.
Aspartate aminotransferase	high	—	A raised AST, with ALT, can make a doctor suspect it; AST is also one input to the FIB-4 scarring score.
Gamma-glutamyl transferase	high	—	GGT may be 2-3 times the upper limit in more than half of patients.

How it usually feels

Feeling tired all the time · occasional
Pain under the right ribs · occasional

Frequencies say how often a symptom accompanies this condition — not the other way round. Most people with any of these symptoms do not have this.