ALD/NAFLD Index (ANI)
ANI (ALD/NAFLD Index) helps clarify the cause of fatty liver disease: alcohol-related (alcoholic liver disease, ALD) or metabolic (NAFLD). It is especially useful when the alcohol history is unclear, and it stays informative even after six months of abstinence. It is calculated from ALT, AST, MCV and BMI.
What ANI is and when you need it
Fatty liver damage comes in two forms: alcohol-related and metabolic (on the background of excess weight and disrupted metabolism). From lab tests alone the two are easy to confuse, yet the treatment depends on the cause. ANI (ALD/NAFLD Index) is an index that uses routine blood values and body data to estimate which of the two causes is more likely.
Its main value is in situations where the history of alcohol use is unclear or unreliable. Moreover, the ANI result stays informative even after 6 months of abstinence — that is, it picks up traces that persist longer than the fact of recent drinking itself.
NAFLD and steatohepatitis
Non-alcoholic (metabolic dysfunction–associated) fatty liver disease (NAFLD) is a chronic liver disease linked to metabolic dysfunction, in which macrovesicular steatosis is found in more than 5% of hepatocytes.
Steatohepatitis is the accumulation of fat in the liver accompanied by intralobular inflammation, ballooning degeneration of hepatocytes and possible progression to fibrosis. It can be both alcohol-related and non-alcoholic — and ANI was created precisely to tell these two apart.
What's needed for the calculation
ANI is calculated from several values and your sex:
- ALT and AST, U/L. Liver enzymes; the index uses precisely their ratio — in alcohol-related damage AST usually outweighs ALT.
- Mean corpuscular volume (MCV), fL. Alcohol enlarges red blood cells, so a raised MCV tilts the result toward an alcohol-related cause.
- BMI. It is calculated automatically from height and weight; a high BMI argues for a metabolic cause.
- Sex. It is accounted for in the formula, since values differ between men and women.
So that extreme lab values don't distort the result, the model applies careful limits to MCV and the enzyme ratio. The calculator below performs the correct calculation.
How to measure correctly
Take ALT, AST and MCV from your blood test reports (MCV comes from the complete blood count). Measure height and weight under the same conditions.
Height
Measure without shoes, standing straight, heels together, looking horizontally.
Weight
Weigh yourself on the same scale, ideally in the morning, on an empty stomach, in light clothing or without it.
ANI Calculator
Enter your sex, height, weight and three blood values — the calculator will compute the ANI index, estimate the likely cause of liver damage and explain the result. The calculation runs on the server.
ANI interpretation thresholds (Dunn et al.): <−2.2 — NAFLD more likely, −2.2…2.2 — grey zone, >2.2 — alcoholic liver disease likely.
How to read the result
ANI is not a “more is worse / less is better” scale but a direction pointer. Two thresholds (−2.2 and +2.2) split the result into three zones.
| Zone | ANI | What it means |
|---|---|---|
| NAFLD likely | < −2.2 | A metabolic (non-alcoholic) cause is more likely. |
| Grey zone | −2.2…2.2 | The cause cannot be assigned with certainty — other data are needed. |
| ALD likely | > 2.2 | Alcoholic liver disease is more likely. |
A metabolic (non-alcoholic) cause is more likely.
The cause cannot be assigned with certainty — other data are needed.
Alcoholic liver disease is more likely.
What each zone means
ANI < −2.2 — NAFLD likely
A negative ANI below −2.2 corresponds to a higher likelihood of non-alcoholic (metabolic dysfunction–associated) fatty liver disease. It directs attention to metabolic factors — weight, diet, blood sugar, lipids — and to the steatosis indices FLI and HSI.
−2.2…2.2 — grey zone
An intermediate result: the index cannot confidently attribute the damage to an alcohol-related or a metabolic cause. Here other data decide — history, additional tests, changes over time — along with a physician's assessment.
ANI > 2.2 — ALD likely
An ANI above 2.2 points to a higher likelihood of alcoholic liver disease. This is not a verdict or a diagnosis, but a reason to honestly discuss the role of alcohol with your physician — even if it seems there is none.
Why MCV and the AST/ALT ratio give away alcohol
- MCV (mean corpuscular volume). Regular alcohol use enlarges red blood cells, so a raised MCV is an indirect but persistent trace of alcohol that lasts for weeks.
- The AST/ALT ratio. In alcohol-related liver damage AST usually outweighs ALT (the ratio rises), whereas in metabolic damage it is more often the other way around.
- BMI. A high body mass index shifts the estimate toward a metabolic cause, a low one toward an alcohol-related cause.
ANI combines these signals into a single number, so it works better than any value on its own, and it doesn't require an honest answer about alcohol, which isn't always available.
Its place in the section and other indices
ANI answers the question “why,” not “how much.” That is why it complements the other liver tools: FLI and HSI estimate the likelihood of steatosis itself, LAP — visceral obesity as the metabolic background, while ANI — the likely nature of the damage. Together they give a fuller picture, which a physician interprets.
Limitations and important caveats
- It is not a diagnosis. ANI estimates the likely cause; it does not confirm alcohol-related or metabolic liver disease.
- It is not a severity assessment. The index does not say how damaged the liver is and does not measure fibrosis.
- The grey zone is a common outcome. A result of −2.2…2.2 is not an error but a signal that other data are needed.
- It depends on test quality. Errors in MCV, ALT, AST or in height and weight measurements shift the result.
- It does not replace the conversation about alcohol. ANI helps the physician but does not replace history-taking and examination.
Frequently asked questions
Where do I find MCV?
MCV (mean corpuscular volume) is in the results of a complete (clinical) blood count — it's a standard value, and there's no need to test for it separately.
Does ANI work if I haven't drunk for a long time?
Yes. A feature of ANI is that it stays informative even after 6 months of abstinence — because it relies on values (for example, MCV) that change slowly.
Does a high ANI mean I'm an alcoholic?
No. A high ANI only says that the blood picture looks more like an alcohol-related cause of damage. It's a reason to discuss the matter with a physician, not a diagnosis or a label.
How does ANI differ from FLI, HSI and LAP?
Those indices estimate whether there is fat in the liver and how pronounced visceral obesity is. ANI answers a different question — what the cause of the damage is: alcohol-related or metabolic.
What should I do with the result?
Show it to your physician along with your test results. ANI is a hint about where to look: with a “metabolic” lean, focus on weight and metabolism; with an “alcohol-related” one, on the role of alcohol. The decision is made by the physician.
