Distinguishes between alcoholic liver disease and non-alcoholic fatty liver disease to help with ALD diagnosis.

You can read more about this hepatic steatosis model in the text below the calculator.

The ALD/NAFLD index uses BMI, MCV and the AST/ALT ratio to distinguish between alcoholic liver disease and non-alcoholic fatty liver disease in patients with steatohepatitis.

The model helps clinicians understand the cause of the hepatic steatosis and adapt patient management appropriately.

The derived nomogram, the ANI formula is:

ANI = -58.5 + 0.637 (MCV) + 3.91 (AST/ALT) – 0.406 (BMI) + 6.35 for male gender

Please note that according to the original study by Dunn et al there is a correction applied to MCV and AST/ALT ratio.

The probability of ALD compared to NAFLD is:

P = eANI/ (1+ eANI)

Where ANI >0 indicates ALD and ANI <0 indicates NAFLD.

Body Mass Index (BMI)
Mean corpuscular value (MCV)
Aspartate Transaminase (AST)
Alanine Transaminase (ALT)
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ANI explained

It is essential for clinicians to differentiate between the cause of steatohepatitic liver injury (whether is due to alcoholic or non-alcoholic factors) because of the different patient management and involvement with candidacy for liver transplantation.

The original study by Dunn et al. involved a cohort of 241 patients with histological evidence of steatohepatitis who underwent liver biopsy.

From these, 25 patients had been diagnosed with other liver disease than ALD or NAFLD.

From the remaining patients, 52 were diagnosed with ALD taking into account their alcohol consumption history, 151 were diagnosed with NAFLD and 13 were excluded because of equivocal alcohol intake or lack of alcoholic history on file.

Using multivariable logistic regression analysis, the following variables were identified as independent predictors of ALD:

■ High MCV (mean corpuscular volume);

■ High AST/ALT ratio;

■ Low body mass index;

■ Male gender.

The derived nomogram, the ANI formula is:

ANI = -58.5 + 0.637 (MCV) + 3.91 (AST/ALT) – 0.406 (BMI) + 6.35 for male gender


According to the original study by Dunn et al., two corrections are applied where required, to lessen the influence of extreme laboratory results. The MCV correction range is set at 92 – 103, meaning that values below 92 and greater than 103 are corrected to the lower, respectively the higher range value. The AST/ALT ratio cannot be greater than 3, meaning that all ratio values greater than 3 are corrected to 3.

The probability of ALD compared to NAFLD is:

P = eANI/ (1+ eANI)

The resulting ANI value has two interpretations:

■ ANI >0: incrementally favours diagnosis of alcoholic liver disease;

■ ANI <0: indicates higher likelihood of non-alcoholic fatty liver disease diagnosis.

The result obtained in the index, remains valid even after 6 months of alcohol abstinence.

The model was found to accurately differentiate between the two liver conditions and was recommended for use in hospitalized, ambulatory, and pretransplantation patients.

Please note that the ANI score has been validated in a single-liver disease population only.


Hepatic steatosis predictors

The following table summarizes other tools for NAFLD screening and their variables:

NAFLD screening tool Patient data required
Fatty Liver Index (FLI) Body mass index, waist circumference, triglycerides, GGT
TyG Index Triglycerides, glucose
Hepatic Steatosis Index (HSI) Body mass index, gender, AST, ALT, presence or absence of type 2 diabetes
ALD/NAFLD Index (ANI) Body mass index, gender, mean corpuscular value, AST, ALT
Non-Alcoholic Fatty Liver Disease - Liver Fat Score (NAFLD-LFS) Presence of absence of metabolic syndrome or type 2 diabetes, insulin levels, AST, ALT

Original source

Dunn W, Angulo P, Sanderson S, Jamil LH, Stadheim L, Rosen C, Malinchoc M, Kamath PS, Shah VH. Utility of a new model to diagnose an alcohol basis for steatohepatitis. Gastroenterology. 2006; 131(4):1057-63.

Article reviewed by Dr. Antonio Olveira

Specialty: Hepatology

System: Digestive

Objective: Differentiation

Type: Index

No. Of Variables: 5

Year Of Study: 2006

Abbreviation: ANI

Article By: Denise Nedea

Published On: September 11, 2017

Last Checked: September 11, 2017

Next Review: September 11, 2023