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Calculate HOMA-IR, HOMA-B beta cell function, and QUICKI index from fasting insulin and glucose to assess insulin resistance severity.
Hepatic Steatosis Index Calculator
Calculate the Hepatic Steatosis Index (HSI) to screen for non-alcoholic fatty liver disease using ALT, AST, BMI, diabetes status, and sex.
⚠️ Medical Disclaimer: The HSI is a screening tool for non-alcoholic fatty liver disease. It estimates steatosis likelihood but does not diagnose fibrosis, NASH, or the cause of abnormal liver tests by itself.
HSI Score⧉
38
Hepatic Steatosis Index. < 30 rules out NAFLD, ≥ 36 rules in NAFLD (AUROC 0.81).
HSI Classification⧉
NAFLD Likely
HSI 38: NAFLD Likely. Validated in Korean and European populations.
ALT/AST Ratio⧉
1.25
Ratio > 1 favors NAFLD; ratio < 1 in advanced fibrosis/cirrhosis. Normal ALT: 7-56 U/L.
Steatosis Estimate⧉
Possible mild steatosis (S1)
Estimated steatosis band based on HSI score. Higher scores commonly prompt imaging review in context.
Fatty Liver Index (FLI)⧉
68 — Suggests fatty liver
Independent fatty liver prediction using BMI, waist, GGT, and triglycerides. FLI < 30 rules out, ≥ 60 rules in.
Risk Factors Present⧉
2 / 6
Number of NAFLD risk factors identified in your profile.
HSI: 38 — NAFLD Likely
0303660+
NAFLD Risk Factor Assessment
| Risk Factor | Status |
|---|---|
| Obesity (BMI ≥ 30) | ✓ Absent |
| Type 2 Diabetes | ✓ Absent |
| Elevated ALT (> 40 U/L) | ✓ Absent |
| ALT/AST Ratio > 1 | ⚠ Present |
| Elevated Triglycerides (≥ 150) | ⚠ Present |
| Central Obesity (waist ≥ 102M/88F) | ✓ Absent |
HSI Score Interpretation
| HSI Score | Interpretation | Sensitivity | Specificity | Typical Follow-up Context |
|---|---|---|---|---|
| < 30 | NAFLD unlikely | 93.1% | 92.4% | Lower screening concern in this tool |
| 30–36 | Indeterminate | — | — | Borderline zone where broader review often matters |
| ≥ 36 | NAFLD likely | 92.5% | 85.2% | Higher screening concern; imaging is commonly used for confirmation |
Planning notes, formulas, and examples
About the Hepatic Steatosis Index Calculator
The Hepatic Steatosis Index (HSI) is a validated, non-invasive screening tool for detecting non-alcoholic fatty liver disease (NAFLD) using routinely available laboratory values and clinical parameters. Developed by Lee et al. in the original Korean cohort study and subsequently validated in European and multi-ethnic populations, the HSI uses ALT/AST ratio, BMI, diabetes status, and sex to estimate the probability of hepatic steatosis.
NAFLD affects approximately 25% of the global population and is a leading cause of chronic liver disease worldwide. It encompasses a spectrum from simple steatosis (fatty liver) to non-alcoholic steatohepatitis (NASH), which can progress to fibrosis, cirrhosis, and hepatocellular carcinoma. Screening tools like the HSI help flag who may need closer review, but they do not stage disease on their own.
This calculator computes the HSI score with validated cutoff interpretation (< 30 rules out NAFLD, ≥ 36 rules in), additionally calculates the Fatty Liver Index (FLI) when triglycerides, waist circumference, and GGT are available, and summarizes common metabolic risk factors for context.
When This Page Helps
The HSI calculator enables efficient NAFLD screening using routine blood work without immediate imaging. It is mainly useful for sorting patients into lower-, indeterminate-, and higher-screening-concern bands.
How to Use the Inputs
- Enter serum ALT and AST values in U/L from available blood work
- Input your BMI in kg/m²
- Indicate whether you have been diagnosed with type 2 diabetes
- Select your biological sex
- Optionally enter waist circumference, triglycerides, and GGT for the Fatty Liver Index
- Review the HSI score, classification, and risk factor assessment
Formula used
HSI = 8 × (ALT/AST ratio) + BMI + 2 (if diabetes) + 2 (if female). Score < 30: NAFLD ruled out (sensitivity 93.1%). Score ≥ 36: NAFLD ruled in (specificity 92.4%). AUROC = 0.812.Example Calculation
Result: HSI: 38.0 — NAFLD Likely
ALT/AST ratio = 1.25, so HSI = 8 × 1.25 + 28 + 0 + 0 = 38.0. Score ≥ 36 places the result in the higher screening-concern band where imaging review is commonly considered.
Tips & Best Practices
- Use the HSI as a first-line screening tool rather than a stand-alone diagnosis.
- ALT can be normal in NAFLD—the ALT/AST ratio and BMI are more informative than absolute ALT values
- Combine HSI screening with FIB-4 score if fatty liver is confirmed to assess fibrosis risk
- Weight loss of 5-7% reduces liver fat; 7-10% can improve NASH histology
- The HSI may be less accurate in lean NAFLD patients (BMI < 25) who still have metabolically active visceral fat
NAFLD: A Growing Global Epidemic
Non-alcoholic fatty liver disease has become the most common chronic liver condition worldwide, affecting roughly 25% of adults globally. Its prevalence is even higher in patients with obesity (75-100%), type 2 diabetes (50-75%), and metabolic syndrome (80-90%). The condition is increasingly recognized in lean individuals (lean NAFLD, ~7-20% of cases), particularly in Asian populations.
The NAFLD-NASH-Cirrhosis Spectrum
NAFLD encompasses a disease spectrum: simple steatosis (fatty liver) is generally benign, but approximately 20-30% of patients progress to NASH, characterized by hepatocyte injury, inflammation, and ballooning. NASH can further progress to fibrosis and cirrhosis over years to decades. NASH cirrhosis is projected to become the leading indication for liver transplantation. Early detection through screening tools like HSI enables intervention at the reversible stages.
Emerging Terminology: MAFLD and MASLD
The field is transitioning from NAFLD to MAFLD (Metabolic-Associated Fatty Liver Disease) and MASLD (Metabolic Dysfunction-Associated Steatotic Liver Disease) nomenclature. These positive diagnostic criteria focus on metabolic dysfunction rather than excluding alcohol use, better reflecting the disease pathophysiology. The HSI and similar screening tools remain valid under both naming conventions.
Sources & Methodology
Last updated:
Methodology
This worksheet calculates HSI and optional FLI-style context from routine labs and anthropometrics to screen for steatosis, not stage disease.
Sources
- Lee JH et al. Hepatic steatosis index (Gastroenterology)
- AASLD steatotic liver disease guidance (AASLD)
- Fatty Liver Index validation literature (Liver International / hepatology literature)
Frequently Asked Questions
The HSI is a simple scoring system that predicts the presence of fatty liver disease using easily available clinical data: ALT, AST, BMI, diabetes status, and sex. It was validated with an AUROC of 0.812 for detecting ultrasonography-confirmed NAFLD.
HSI < 30 effectively rules out NAFLD (negative predictive value > 90%). HSI ≥ 36 rules in NAFLD (positive predictive value ~90%). Scores between 30-36 are indeterminate and warrant further evaluation.
Both are validated non-invasive NAFLD screening tools. HSI uses ALT, AST, BMI, diabetes, and sex. FLI uses BMI, waist circumference, triglycerides, and GGT. They have similar diagnostic accuracy (AUROC ~0.80-0.85). Using both provides complementary information.
No, the HSI only estimates the presence of hepatic steatosis (fat accumulation). It cannot distinguish simple steatosis from NASH or assess fibrosis stage. For fibrosis assessment, use FIB-4, NFS, or FibroScan.
Non-alcoholic fatty liver disease (NAFLD) is characterized by excess fat accumulation (≥ 5%) in the liver without significant alcohol consumption. It ranges from simple steatosis to NASH (with inflammation), which can progress to cirrhosis.
Management depends on the broader clinical picture. Lifestyle change is a common first-line theme, but this calculator is a screening aid and does not determine treatment on its own.
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