FibroScan Results Explained: What Your kPa, CAP, and IQR Numbers Mean
If you've just received your FibroScan results and you're not sure what the numbers mean, you're in the right place. This guide explains what each measurement means, what the ranges indicate, and what to do next.
Your FibroScan report contains up to three numbers: a kPa value (liver stiffness), a CAP or dB/m value (liver fat), and sometimes an IQR ratio (result reliability). Here's what each one tells your doctor — and you.
The kPa Result — Liver Stiffness (Fibrosis)
The kPa (kilopascal) number measures how stiff your liver is. Stiffness is caused by scar tissue (fibrosis). A healthy liver is flexible and soft. A scarred liver becomes harder and less elastic.
| kPa Result | Fibrosis Stage | What It Means | What Typically Happens Next |
|---|---|---|---|
| < 7 kPa | F0–F1 | Normal to minimal fibrosis | Monitor with annual FIB-4 blood test; lifestyle management |
| 7–9.5 kPa | F1–F2 | Mild to moderate fibrosis | Clinical review; repeat elastography in 1–2 years; address risk factors |
| 9.5–12 kPa | F2–F3 | Moderate to significant fibrosis | Specialist referral likely; investigate underlying cause |
| 12–15 kPa | F3 | Advanced fibrosis | Specialist referral recommended; further investigation |
| > 15 kPa | F3–F4 / Cirrhosis | Possible cirrhosis | Urgent specialist referral; additional tests to confirm |
Important: These thresholds are approximate guides, not diagnostic cutoffs. They vary depending on what condition is causing the liver disease. Your doctor will interpret your result in context — a kPa of 10 in hepatitis B has different implications to 10 kPa in someone with MAFLD. Always discuss your result with your doctor.
The CAP Score — Liver Fat (Steatosis)
CAP stands for Controlled Attenuation Parameter. It measures how much fat is in your liver, on a scale from roughly 100 to 400 dB/m. More fat in the liver slows down sound waves — a higher CAP number means more fat detected.
| CAP Score | Steatosis Grade | Fat in Liver Cells | Clinical Meaning |
|---|---|---|---|
| < 238 dB/m | S0 — Normal | < 5% | No significant fat accumulation |
| 238–259 dB/m | S1 — Mild | 5–33% | Mild steatosis — often reversible with lifestyle change |
| 260–292 dB/m | S2 — Moderate | 34–66% | Moderate steatosis — warrants clinical assessment and management |
| > 292 dB/m | S3 — Severe | > 67% | Significant fatty liver disease — active management required |
A CAP of 300, for example, puts you in the S3 range — significant steatosis. This is a finding your doctor needs to act on, but it does not mean liver failure. Many people with S3 steatosis successfully reduce their liver fat through weight loss, improved diabetes control, and dietary change.
The IQR Ratio — Was Your Result Reliable?
IQR stands for Interquartile Range. The IQR/Median ratio tells you how consistent the 10 individual measurements were that made up your result. A low IQR means the measurements agreed closely — a reliable result. A high IQR means they varied widely.
IQR/M ≤ 0.30 (30%)
Reliable result — proceed with confidence
IQR/M > 0.30 (30%)
Unreliable result — the scan may not accurately reflect your liver
Unreliable results are common in patients with high BMI, after eating, or if there was patient movement during the scan. If your report shows an unreliable IQR, ask your doctor whether the scan should be repeated — potentially with a guided elastography system, which uses real-time imaging to improve placement accuracy.
What to Do Next
Your FibroScan result is one data point in your overall liver health picture. It is interpreted alongside your blood tests (FIB-4, ALT, AST, GGT), your clinical history, and your risk factors.
If your kPa is above 8 kPa, CAP above 260, or IQR was unreliable
Your doctor will typically review the result in the context of your full history and may refer you to a gastroenterologist or hepatologist for further assessment.
If your result was unreliable and you need a repeat scan
Guided elastography — which uses real-time 2D imaging — achieves higher success rates, particularly in patients with higher BMI. Ask your GP about referral to a guided elastography clinic.
Not sure what your result means?
Find an elastography clinic near you and ask your GP to review your FibroScan report together.
What if I'm scanned on a different device?
Different elastography systems use different methods to measure liver fat. FibroScan uses CAP (Controlled Attenuation Parameter); the iLivTouch guided system uses UAP (Ultrasound Attenuation Parameter). Both measure the same thing — the amount of fat in your liver — and both produce a steatosis grade from S0 to S3.
| FibroScan — CAP | iLivTouch — UAP | |
|---|---|---|
| Full name | Controlled Attenuation Parameter | Ultrasound Attenuation Parameter |
| What it measures | Hepatic steatosis (liver fat content) | Hepatic steatosis (liver fat content) |
| Units | dB/m | dB/m |
| Are the numbers comparable? | NO — absolute dB/m values are NOT directly comparable between CAP and UAP | |
| Clinical output | Steatosis grade S0–S3 | Steatosis grade S0–S3 |
What you cannot do is compare the absolute number directly. A CAP of 280 and a UAP reading from iLivTouch are not on the same scale — like comparing Celsius and Fahrenheit. What matters is the grade (S0, S1, S2, S3), not the raw number.
If you change devices between scans, your doctor will compare grades, not numbers. This is why your report includes the grade interpretation alongside the number. Track your grade over time, not the dB/m figure.
Why this matters: If your FibroScan IQR was unreliable, or you want confirmation of your result with a different technique, guided 2D elastography (iLivTouch) uses real-time imaging to improve placement accuracy — particularly in patients with higher BMI where blind acquisition is more likely to fail. Compare devices →
FibroScan results — common questions
What is the normal range of kPa (E kPa) on FibroScan?
A normal liver stiffness result is generally below 7 kPa for most liver conditions. For MAFLD/MASLD specifically, a result below 8 kPa is typically considered low-risk (F0–F1). Results between 8–12 kPa are indeterminate and usually require clinical review. Above 12 kPa suggests significant fibrosis (F3) and above 15–17 kPa is consistent with cirrhosis. These thresholds vary by disease and the guidelines your doctor is using — always discuss your result with your doctor.
What is the normal range of CAP in FibroScan?
CAP (Controlled Attenuation Parameter) measures liver fat content on FibroScan. The commonly used reference ranges are: below 238 dB/m = S0 (normal, less than 5% fat); 238–259 dB/m = S1 (mild steatosis, 5–33% fat); 260–292 dB/m = S2 (moderate steatosis, 34–66% fat); above 292 dB/m = S3 (severe steatosis, more than 67% fat). Individual thresholds may vary depending on the study protocol. A result above 260 dB/m warrants clinical discussion.
What does a FibroScan CAP score of 300 mean?
A CAP score of 300 dB/m falls in the S2–S3 range, indicating moderate to severe hepatic steatosis — meaning a significant proportion of liver cells (roughly 34–67% or more) contain excess fat. This does not mean your liver is failing, but it does indicate significant fatty liver disease (MAFLD/MASLD) that warrants further assessment and lifestyle management. Your doctor will likely also review your kPa (fibrosis) result alongside this, as the two together give a more complete picture of your liver health.
What is the FibroScan IQR normal range?
IQR/median ratio measures the reliability of your FibroScan result. A ratio of 30% or below (IQR/M ≤0.30) is considered a reliable result. A ratio above 30% means the measurements were inconsistent — often due to high BMI, narrow intercostal space, or patient movement — and the result may not accurately reflect your liver's true stiffness. If your report shows an unreliable IQR, your doctor may recommend repeating the scan, possibly with a different device or technique.
What is the rule of 5 for liver stiffness?
The 'rule of 5' in liver elastography refers to approximate liver stiffness thresholds in multiples of 5 kPa as a quick clinical reference: below 5 kPa is normal; 5–10 kPa suggests mild to moderate fibrosis; 10–15 kPa indicates advanced fibrosis; above 15 kPa raises concern for cirrhosis. Separately, in monitoring patients with established fibrosis, a change of 5 kPa or more between measurements is considered clinically meaningful (Baveno VII). Exact thresholds vary by disease aetiology — always interpret with your clinician.
What are bad FibroScan results?
A 'bad' FibroScan result typically means either a high kPa stiffness reading (suggesting significant fibrosis or cirrhosis) or a high CAP score (suggesting substantial liver fat). A kPa result above 12 kPa warrants specialist review, and above 15 kPa is consistent with cirrhosis. A CAP above 292 dB/m indicates severe steatosis. An unreliable IQR result (above 30%) means the scan quality was insufficient. A high result is not a diagnosis — it is a finding that requires clinical follow-up, not panic.
What does a FibroScan results chart show?
FibroScan results are expressed as two main numbers: kPa (liver stiffness, for fibrosis staging from F0–F4) and CAP dB/m (liver fat, for steatosis staging from S0–S3). The kPa result maps to fibrosis stages: F0–F1 (minimal/no fibrosis, typically <7–8 kPa), F2 (moderate, ~8–10 kPa), F3 (severe, ~10–14 kPa), F4/cirrhosis (>14–15 kPa). The CAP maps to fat grades S0 (<238), S1 (238–259), S2 (260–292), S3 (>292). Exact thresholds vary by condition.
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Medical disclaimer: All content on this page is educational and is not intended as medical advice. Diagnosis and treatment decisions must be made by a qualified healthcare professional. If you have concerns about your liver health, speak with your GP.