AI Summary The Hepatic Steatosis Index (HSI) is a non-invasive score that uses routine results to estimate how likely it is that you have fat in your liver. Doctors may use it if you have risk factors, raised liver enzymes, or need follow-up. A higher number means fat is more likely, but the HSI does not diagnose fatty liver or measure scarring. Ultrasound or other imaging confirms the result. Lifestyle changes, including weight loss, are the foundation of care.
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Medically Reviewed.
The Hepatic Steatosis Index (HSI) is a calculated score. It turns routine results into one number that helps your care team judge whether fat has built up in your liver. That buildup is called hepatic steatosis, or fatty liver.
The HSI is a first look, not a diagnosis. Doctors confirm fatty liver with imaging and other tests. This page explains when the score is used, how to read a result, what it cannot tell you, and what to do next.
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FATTY LIVER SCORE BASICS
The Hepatic Steatosis Index (HSI) is a non-invasive score that estimates the chance of fat in the liver. Hepatic steatosis is the medical term for that fat buildup. You may also hear it called fatty liver or fatty liver disease.
The HSI belongs to the MAFLD / MASH scores group. Like the others in the group, it turns routine results, such as liver enzymes and body measurements, into one number. Getting it does not take a biopsy or a special scan.
Fatty liver that is not caused by heavy alcohol use is now called MASLD (metabolic dysfunction–associated steatotic liver disease). It was formerly called NAFLD. A more serious form, MASH (formerly NASH), adds inflammation and liver damage to the fat. The HSI looks at the first question only: is there likely to be fat in the liver?
The score is an estimate. It does not diagnose fatty liver, and it does not measure scarring.
WHEN DOCTORS USE THE HSI
The HSI is an easy first step. It uses results you may already have, so it can point toward further testing without a procedure.
Fatty liver is common in people with obesity and type 2 diabetes. One-third to two-thirds of people with type 2 diabetes have NAFLD (MASLD), and it is present in up to 75% of people who are overweight. High triglycerides are another risk factor.
People over 50, people with type 2 diabetes, and people with metabolic syndrome should have liver enzymes and ultrasound as part of a routine work-up. A calculated score can be one quick way to add context to those results.
Blood tests are often the first step when a doctor looks for liver problems, and raised enzymes can point toward fatty liver. A score helps your doctor decide whether imaging is the next step.
A score needs no procedure, so it can be repeated. Doctors may use scores like this when they want to follow liver health after you change your diet, activity, or treatment.
UNDERSTANDING YOUR HSI SCORE
The HSI gives you one number. A higher number means fat in the liver is more likely. A lower number means it is less likely.
Most scores in this group sort results into low, intermediate, and high. Here is how doctors generally use those groups:
- Low: Fatty liver is less likely. Your doctor may still look further if you have risk factors or other test changes. - Intermediate: The result is not clear. More testing, usually imaging, helps settle the question. - High: Fatty liver is more likely. Imaging, such as ultrasound, confirms it.
This page does not list cutoff numbers. Cutoffs depend on the score and the study behind it, so use the ranges your lab or care team gives you and ask what your number means for you.
A positive blood-based result should often be followed by confirmatory testing, such as imaging or elastography, before any firm conclusions are drawn.
FATTY LIVER TEST OPTIONS
Each test answers a different question. Doctors often use them in steps.
| Test | What it tells you | How it is done |
|---|---|---|
| Hepatic Steatosis Index (HSI) | How likely it is that fat is in the liver | Calculated from routine results |
| MAFLD Score | How likely metabolic fatty liver is | Calculated from age, BMI, and blood sugar status |
| FIB-4 | How likely liver scarring is (it does not measure fat) | Calculated from age, platelets, AST, and ALT |
| Ultrasound | Whether fat is visible in the liver; the usual first imaging test | Imaging |
| CAP (with FibroScan) | Grades liver fat; about 275 dB/m suggests fatty liver (5% or more fat) | Imaging during elastography |
| MRI-PDFF | The most precise measure of liver fat | MRI scan |
| Liver biopsy | Confirms MASH when other results are unclear | Small tissue sample |
Simple blood-based tests come first, then imaging when a result is indeterminate or high. Biopsy is kept for unclear cases.
HSI ACCURACY AND LIMITATIONS
The HSI estimates fat. It does not show how much scarring (fibrosis) you have. Scores such as FIB-4 are built for that question. A normal fat estimate does not rule out scarring from another cause.
Blood-based scores can give false positive or false negative results in some conditions, such as acute hepatitis, raised bilirubin, Gilbert’s syndrome, or systemic inflammation. Tell your doctor about any other health conditions you have.
The score shows a likelihood, not a diagnosis. Ultrasound and other tests are needed to confirm fatty liver, and a biopsy is used only when results stay unclear.
The HSI does not tell you why fat is in your liver. Heavy alcohol use can cause it, and so can metabolic problems. Your doctor looks at your full history, including alcohol use, to sort this out.
FATTY LIVER FOLLOW-UP STEPS
Your result is a starting point. These steps are common, but your care team will tailor them to you.
FATTY LIVER CARE OPTIONS
There is no single fix for fatty liver. Lifestyle changes are the foundation. If tests later show MASH with scarring, your specialist may discuss medicine. One option is [resmetirom (Rezdiffra)](/liver-therapies/metabolic-masld-mash-therapies/thr-beta-agonist-therapy/resmetirom). Some people who meet surgical criteria may consider [bariatric and endoscopic therapies](/liver-therapies/metabolic-masld-mash-therapies/bariatric-endoscopic-therapies), which can improve MASH and fibrosis.
Read more about the condition on our fatty liver disease(/liver-diseases/metabolic-liver-diseases/fatty-liver-disease) page.
A balanced, liver-friendly diet supports your liver, helps manage weight and blood sugar, and lowers the risk of other health problems during long-term follow-up.
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Common Questions
No. The HSI estimates how likely it is that you have fat in your liver, but it does not diagnose fatty liver. MASLD is diagnosed by combining imaging and lab evaluation. Ultrasound is the first imaging step, and MRI-PDFF measures liver fat precisely. The lab work can include liver enzymes, fasting glucose, HbA1c, a lipid panel, and scarring scores such as FIB-4. A biopsy is kept for cases where the diagnosis stays uncertain. Think of the HSI as a first look. It helps your doctor decide which of these tests to order next.
A higher HSI means fat in the liver is more likely, and a lower one means it is less likely. This page does not list a single normal number, because cutoffs depend on the score version and the study behind it. Most scores in this group sort results into three groups. A low result means fatty liver is less likely, though your doctor may still look further if you have risk factors. An intermediate result is not clear, and imaging usually helps settle it. A high result means fatty liver is more likely, and imaging confirms it. Ask your care team which range applies to your result and what it means for you.
Not by itself. A high score is a reason for follow-up, not a sign of serious damage. The HSI looks at fat only. How serious fatty liver is depends mostly on whether it has caused inflammation and scarring, which the HSI does not measure. A positive blood-based result should often be followed by confirmatory testing before firm conclusions are drawn. Your doctor will usually confirm the result with an ultrasound or another liver fat test. If fat is confirmed, the next step is a scarring check. Non-invasive tests are preferred for this, such as FIB-4, elastography, or the ELF score. A biopsy is considered only when those results are unclear.
No. The HSI looks at fat only. Fat and scarring (fibrosis) are two separate questions. Scores such as FIB-4 estimate scarring, and FIB-4 does not measure fat. It is calculated from age, platelets, AST, and ALT. A normal fat estimate does not rule out scarring from another cause. Doctors often use the two kinds of test together. A stepwise approach is recommended: a simple blood-based test first, then imaging such as elastography if the result is unclear or high.
Yes, lifestyle changes can reduce liver fat, which is what the HSI estimates. Your doctor can tell you how often to repeat your tests and whether your score has changed. The main points are: - **Weight loss:** Losing 3% to 5% of body weight can improve liver fat. More than 10% is often needed to improve inflammation and scarring. - **Diet:** A Mediterranean-style diet with limited saturated fat and refined carbohydrates is recommended. - **Activity:** Regular physical activity helps liver fat even without weight loss. If you already have a liver condition, avoid alcohol. If you smoke, ask your doctor for help to quit.
Medical disclaimer: LiverDirectory provides educational information and a directory of providers. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed physician regarding any medical condition.
