Diagnosing and staging fatty liver disease
Finding fat in the liver is easy; the real question is how much scarring is there. Today that can be answered in most patients with a blood-test score and a 10-minute scan — no biopsy. Here is who should be checked, what each test means, and the thresholds at which we bring in a liver specialist.
Key takeaways
- Adults with type 2 diabetes, prediabetes with risk factors, obesity with metabolic risk, or fatty liver on imaging should have a fibrosis risk check.
- Step 1 is FIB-4, calculated from age, AST, ALT and platelets. <1.3 is low risk; anything higher needs a second test.
- Step 2 is elastography (FibroScan) or an ELF blood test. A liver stiffness <8 kPa is reassuring; >12 kPa suggests advanced fibrosis.
- Advanced fibrosis or cirrhosis is referred to hepatology; coronary disease and complex lipid disorders to cardiology — while we keep treating the metabolism.
What this means for you
If you have diabetes or a fatty liver, ask for your FIB-4 — it can be calculated from blood work you have probably already had. If it isn't clearly low, a FibroScan tells us whether you need liver-directed treatment, routine monitoring, or a hepatologist.
Who should be checked
The ADA, AACE, AASLD and European guidelines converge on the same high-risk groups for MASLD with fibrosis:
- Type 2 diabetes — all adults (ADA Standards of Care recommend FIB-4 screening even with normal liver enzymes).
- Prediabetes, especially with obesity or other cardiometabolic risk factors.
- Obesity with two or more metabolic risk factors — high blood pressure, high triglycerides or low HDL, elevated glucose.
- Fatty liver seen on any imaging, or persistently elevated ALT or AST.
- First-degree relative with cirrhosis from MASH.
Before attributing liver fat to metabolism, we make sure alcohol use is characterized and that other liver diseases (viral hepatitis, iron overload, autoimmune liver disease, medication effects) are not the explanation.
Step 1: FIB-4 and other blood tests
FIB-4 is a free score calculated from four routine values: (age × AST) ÷ (platelet count × √ALT). It is designed to rule out advanced fibrosis — and it does that well.
| FIB-4 | Risk of advanced fibrosis | Next step |
|---|---|---|
| <1.3 | Low | Treat metabolic risk; repeat FIB-4 in 1–3 years (sooner with diabetes or worsening risk) |
| 1.3–2.67 | Indeterminate | Second-line test: elastography or ELF |
| >2.67 | High | Elastography, and referral to hepatology if confirmed |
Two caveats matter. FIB-4 is less reliable under age 35, and it rises with age alone — many experts use a low-risk cutoff of 2.0 in people 65 and older. And a normal ALT does not lower the concern: FIB-4 is useful precisely because liver enzymes miss most fibrosis.
ELF (Enhanced Liver Fibrosis) is a proprietary blood test of three markers of scar turnover. It is a good second-line option when elastography is not available: <7.7 low risk, 7.7–9.8 intermediate, ≥9.8 high risk of advanced fibrosis.
Step 2: FibroScan and MRI
Vibration-controlled transient elastography (VCTE, "FibroScan") is a 10-minute, painless ultrasound-based test that measures two things at once:
- Liver stiffness (LSM, in kPa) — stiffer liver means more scar.
- Controlled attenuation parameter (CAP, in dB/m) — an estimate of liver fat.
Other options include shear-wave elastography on standard ultrasound machines, and MRI-based tests — MR elastography (MRE), the most accurate noninvasive measure of stiffness, and MRI-PDFF, the most accurate measure of liver fat. Cutoffs differ between machines, so results should be read against the device used.
Fibrosis stages and risk tiers
| Liver stiffness (FibroScan) | What it suggests | What we do |
|---|---|---|
| <8 kPa | No or mild fibrosis (F0–F1) | Treat the metabolism; re-check in 1–3 years |
| 8–12 kPa | Possible moderate fibrosis (F2), sometimes F3 | Intensify treatment; consider liver-directed medication; confirm with a second test when unclear |
| >12 kPa | Likely advanced fibrosis (F3) | Liver-directed medication and co-management with hepatology |
| ≥20 kPa, or low platelets / nodular liver | Probable cirrhosis (F4) | Hepatology-led care, including liver-cancer and varices surveillance |
These are the thresholds used in AASLD and AACE pathways. Liver biopsy remains the reference standard but is not routinely needed; we reserve it, through hepatology, for cases where results are discordant or another diagnosis is possible.
For cliniciansIdentifying candidates for MASH pharmacotherapy
AASLD guidance on resmetirom supports noninvasive identification of noncirrhotic F2–F3 MASH, for example VCTE LSM roughly 8–20 kPa (or MRE 3.0–5.0 kPa, or ELF 9.2–11.3) with evidence of steatosis, after excluding other liver disease and cirrhosis. Stiffness of 15–20 kPa can reflect F3 when there are no clinical, laboratory or imaging signs of cirrhosis. Baseline labs include CMP, CBC with platelets, A1c, lipid panel and TSH; we document CAP, LSM and FIB-4 so treatment response can be tracked. Confounders of LSM include recent meals, ALT flares, congestion and cholestasis; CAP can be unreliable with high BMI unless the XL probe is used.
When we refer to hepatology or cardiology
We are endocrinologists. We screen, stage, and treat the metabolic disease that drives MASLD, and we manage patients with moderate fibrosis — including prescribing liver-directed medication. But we are explicit about where the liver or the heart needs a specialist, and we refer early rather than late.
| Finding | Who leads |
|---|---|
| MASLD with low fibrosis risk (FIB-4 <1.3 or LSM <8 kPa) | Our practice — metabolic treatment and periodic re-staging |
| MASH with moderate fibrosis (F2; LSM ~8–12 kPa) | Our practice — including semaglutide or resmetirom when indicated |
| Advanced fibrosis (F3; FIB-4 >2.67, LSM >12 kPa, or ELF ≥9.8) | Referred to gastroenterology / hepatology for co-management; we continue metabolic care |
| Cirrhosis or suspected cirrhosis (LSM ≥20 kPa, low platelets, nodular liver, varices) | Hepatology leads — liver-cancer and varices surveillance, transplant evaluation when needed |
| Any sign of decompensation: jaundice, ascites, confusion, GI bleeding | Urgent hepatology (emergency care for bleeding or confusion) |
| A liver mass, or another liver disease suspected | Hepatology |
| Established or suspected coronary artery disease, heart failure or arrhythmia | Cardiology |
| Severe or complex lipid disorders — suspected familial hypercholesterolemia, LDL not at goal on standard therapy, very high triglycerides | Cardiology / lipid specialist |
| Advanced chronic kidney disease | Nephrology |
Questions to ask your doctor
- What is my FIB-4, and has it changed over time?
- Should I have a FibroScan — and what were my stiffness (kPa) and CAP numbers?
- Do my results put me in the range for liver-directed medication?
- Do I need to see a hepatologist or a cardiologist?
How we grade evidence. Every intervention carries a plain label — from established, guideline-supported care (A) through moderate (B) and mixed or limited (C) to experimental (D) and insufficient (E). An improvement on a liver biopsy or scan is not the same as fewer cirrhosis cases, heart attacks, or deaths, and we say which we mean.
Common questions about liver testing and results.
My FIB-4 is 1.6. Is that bad? Grade A
What the evidence shows
Guideline pathways (AASLD, AACE, ADA, EASL) all use FIB-4 <1.3 to rule out advanced fibrosis and send indeterminate scores for a second test.
In our practice
We order elastography for anyone with FIB-4 ≥1.3 (≥2.0 if 65 or older) and interpret it alongside the full metabolic picture.
Do I need a liver biopsy? Grade A
What the evidence shows
Current AASLD guidance supports noninvasive tests for identifying F2–F3 disease and starting therapy; biopsy is reserved for uncertain or discordant cases.
In our practice
If a biopsy is needed, it is arranged through hepatology.
My FibroScan was 13 kPa. What happens now? Grade A
What the evidence shows
Liver stiffness above 12 kPa has high specificity for advanced (F3–F4) fibrosis, and liver-related risk climbs steeply at this stage.
In our practice
We refer to gastroenterology/hepatology and coordinate treatment so nothing falls between specialties.
References
- American Diabetes Association Professional Practice Committee. 4. Comprehensive medical evaluation and assessment of comorbidities: Standards of Care in Diabetes—2025. Diabetes Care. 2025;48(Suppl 1):S59–S85.
- Cusi K, et al. American Association of Clinical Endocrinology clinical practice guideline for the diagnosis and management of nonalcoholic fatty liver disease in primary care and endocrinology clinical settings. Endocr Pract. 2022;28(5):528–562.
- Rinella ME, et al. AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease. Hepatology. 2023;77(5):1797–1835.
- Kanwal F, et al. Clinical care pathway for the risk stratification and management of patients with nonalcoholic fatty liver disease. Gastroenterology. 2021;161(5):1657–1669.
- EASL–EASD–EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD). J Hepatol. 2024;81(3):492–542.
- Sterling RK, et al. AASLD practice guideline on imaging-based noninvasive liver disease assessment of hepatic fibrosis and steatosis. Hepatology. 2025;81(2):672–724.
- Chen VL, et al. Resmetirom therapy for metabolic dysfunction-associated steatotic liver disease: October 2024 updates to AASLD Practice Guidance. Hepatology. 2025;81(1):312–320.
- Lomonaco R, et al. Advanced liver fibrosis is common in patients with type 2 diabetes followed in the outpatient setting. Diabetes Care. 2021;44(2):399–406.
Want your liver staged — and a clear plan for what the numbers mean?
FIB-4, elastography, and a straight answer about whether you need treatment or a hepatologist.