ALD/NAFLD Index (ANI) Calculator

ALD/NAFLD Index (ANI) Calculator for Endocrinology. Positive scores lean toward the alcohol-associated group in the original comparison; negative scores lean toward the nonalcoholic group. The displayed logistic transformation is 100 / (1 + exp(-ANI)), conditional on that historical two-group model, not a contemporary individualized diagnosis.

For shared guidance on choosing a tool and documenting results, read the clinical calculator workflow.

How this calculator works

ANI = -58.5 + 0.637 x adjusted MCV + 3.91 x adjusted AST/ALT - 0.406 x BMI + 6.35 for male sex. Before calculation, MCV is limited to 92-103 fL and AST/ALT to a maximum of 3. These are model transformations, not corrections to the laboratory report.

When to use this calculator

Use as historical model arithmetic in an already evaluated steatohepatitis differential. Other causes of liver disease must be considered first. The model does not establish whether a person is drinking, and it must not be used to judge honesty or transplant eligibility.

Inputs used

  • AST and ALT in U/L
  • MCV in fL
  • BMI in kg/m2
  • Sex convention used in the original model

Clinical interpretation

Positive scores lean toward the alcohol-associated group in the original comparison; negative scores lean toward the nonalcoholic group. The displayed logistic transformation is 100 / (1 + exp(-ANI)), conditional on that historical two-group model, not a contemporary individualized diagnosis.

Worked example

The original illustrative male case uses MCV 104, AST/ALT 4 and BMI 40. After truncation, -58.5 + 0.637 x 103 + 3.91 x 3 - 0.406 x 40 + 6.35 = 8.951. The source female example, MCV 95, ratio 1 and BMI 27, gives -5.037.

Limitations and safety notes

Advanced decompensation reduced discrimination in the original study. Alcohol-associated and metabolic contributions can coexist; current MASLD/MetALD categories are not recovered by a universal zero cutoff. Abstinence does not reliably normalize ANI. Input bounds are software safeguards, not validated clinical ranges.

Frequently asked questions

Why did changing MCV from 104 to 110 leave the answer unchanged?

Both are mapped to the original model ceiling of 103 fL. The measured values themselves have not changed.

Does the percentage detect recent alcohol use?

No. It is a model transformation, not a drinking biomarker or evidence about current behavior.

References

  • Original Dunn full text as indexed: MCV 92-103 truncation, AST/ALT ceiling 3, logistic probability, worked examples and limitations of alcohol-use detection. https://pmc.ncbi.nlm.nih.gov/articles/PMC2483536/
  • Independent primary cohort methods: ANI coefficients corroborated; not used as evidence for diagnostic accuracy. https://link.springer.com/article/10.1186/s12876-024-03222-x
  • Developer institution: intended differential, other-cause exclusions, MELD limitations and not a test of surreptitious alcohol use. https://www.mayoclinic.org/medical-professionals/transplant-medicine/calculators/the-alcoholic-liver-disease-nonalcoholic-fatty-liver-disease-index-ani/itt-20434726
  • Primary 2024 study: contemporary MASLD/MetALD classification context, not automatic transfer of new thresholds. https://pmc.ncbi.nlm.nih.gov/articles/PMC11443332/

Editorial review and citation methodology

Maintained by the Quick Medical Calculator Editorial Team. Content record date: September 9, 2026. A content date is not evidence of independent clinical review. Individual clinical sign-off is not recorded on this page.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

Related reviewed calculators