FibroSure Test for Fatty Liver: Results Explained

The FibroSure test for fatty liver is a validated blood-based panel that estimates liver fibrosis severity without the need for a biopsy. Also known as FibroTest, it analyses five serum biomarkers alongside age and sex to produce a composite score mapped to histological fibrosis stages. In the context of fatty liver disease, including MASLD and alcohol-related liver disease, it can help identify patients with minimal or advanced fibrosis. This article explains how the test works, what your results mean, who may benefit from it in the UK, and where it fits within current NICE guidance on liver disease assessment.

What is the FibroSure test and how does it work?

FibroSure is a proprietary blood panel that estimates liver fibrosis and necroinflammatory activity using five serum markers, age, and sex, producing a composite score between 0 and 1.00 without requiring a liver biopsy.

FibroSure is a validated blood-based biomarker panel used to assess liver fibrosis and necroinflammatory activity without the need for a liver biopsy. Developed in France and used in specialist hepatology settings, it is marketed under the name FibroTest in many regions, including the UK, where both names refer to the same proprietary assay.

The panel produces two related but distinct outputs. FibroTest estimates the degree of liver fibrosis using five serum markers: alpha-2-macroglobulin, haptoglobin, apolipoprotein A1, total bilirubin, and gamma-glutamyl transferase (GGT), combined with the patient's age and sex. ActiTest estimates necroinflammatory activity and incorporates the same five markers plus alanine aminotransferase (ALT).^[1] The two outputs are commonly reported together, but they measure different aspects of liver disease and should be interpreted accordingly.

The algorithm generates a composite score between 0 and 1.00, which is then mapped onto a histological staging system. Because it relies on a standard blood draw, it is considerably less invasive than a percutaneous liver biopsy, which carries a small but real risk of bleeding and discomfort.

FibroSure/FibroTest is a proprietary test and is not universally available through NHS laboratories. Access in the UK depends on local specialist hepatology pathways and whether the test is offered by an accredited laboratory. Patients may encounter it through specialist hepatology units, private laboratories, or clinical research settings. Results require careful interpretation by a clinician familiar with the scoring system, as several conditions unrelated to liver disease can influence individual biomarker levels and therefore affect the composite result.

Can FibroSure detect fatty liver and measure fibrosis severity?

FibroSure estimates fibrosis severity in fatty liver disease but does not directly quantify liver fat; a separate output, SteatoTest, incorporates additional markers such as glucose and triglycerides to assess steatosis.

FibroSure can provide indirect evidence of liver disease associated with fatty liver conditions and, more reliably, can estimate the degree of liver fibrosis, though it does not directly image or quantify fat content within liver tissue. Fatty liver disease, whether alcohol-related (ALD) or metabolic dysfunction-associated steatotic liver disease (MASLD, previously known as non-alcoholic fatty liver disease or NAFLD), can progress through stages of fibrosis from F0 (no fibrosis) to F4 (cirrhosis). FibroTest was originally validated in chronic hepatitis C and hepatitis B, and published evidence also supports its use in MASLD and alcohol-related liver disease, though performance may vary by disease aetiology.^[1][2]

The FibroSure score correlates with the METAVIR histological staging system, which classifies fibrosis on a scale of F0 to F4.^[1] A score closer to 0 suggests minimal or no fibrosis, while a score approaching 1.00 is associated with advanced fibrosis or cirrhosis. In the context of fatty liver disease, the test is most useful for identifying patients at the extremes, those with clearly minimal disease or those with significant fibrosis, rather than those in the intermediate range.

For estimating steatosis (fat accumulation), a related component called SteatoTest incorporates additional markers such as glucose, triglycerides, cholesterol, and body mass index. SteatoTest is a separate output from FibroTest and should not be conflated with it.

In UK clinical practice, NICE guidance (NG49) recommends liver ultrasound to detect steatosis and a stepwise approach to fibrosis risk stratification, beginning with FIB-4 or the NAFLD Fibrosis Score in primary care, followed by the enhanced liver fibrosis (ELF) test to identify advanced fibrosis.^[2] Transient elastography with controlled attenuation parameter (CAP) measurement is used in many specialist services to assess both stiffness and steatosis, though it is not specifically mandated by NICE.^[4][5] FibroSure is not part of the NICE-recommended primary care pathway but may be used in specialist centres where it has been locally adopted.

What do your FibroSure results actually mean?

A FibroSure score closer to 0 suggests minimal or no fibrosis, while a score approaching 1.00 indicates advanced fibrosis or cirrhosis, though indeterminate results are common and require further clinical investigation.

A FibroSure score is reported as a number between 0 and 1.00, and understanding what that number means requires mapping it onto established fibrosis stages and considering the clinical context alongside it. Published interpretive guides from the assay developer suggest that lower scores are broadly associated with minimal or no fibrosis (F0 to F1) and higher scores with advanced fibrosis or cirrhosis (F3 to F4), but the precise numerical thresholds vary by disease aetiology and laboratory calibration. Clinicians should use the interpretive ranges provided by the reporting laboratory rather than applying fixed cut-offs from a different clinical context.

When results fall in the indeterminate range, which is common, clinicians typically consider additional investigations. In line with NICE NG49, the stepwise approach in the UK begins with FIB-4 or the NAFLD Fibrosis Score in primary care, followed by ELF testing to identify advanced fibrosis, and then specialist referral where indicated. FibroSure may be used within a specialist pathway as a complementary or confirmatory tool where locally available, but it is not a NICE-endorsed step in the standard pathway.

Several factors can cause a falsely elevated or falsely low FibroSure score. These include:

• Acute inflammation or infection, which raises alpha-2-macroglobulin and bilirubin

• Haemolysis, which artificially lowers haptoglobin

• Gilbert's syndrome, which raises bilirubin independently of liver disease

• Extrahepatic cholestasis, which elevates GGT and bilirubin

For this reason, results should always be interpreted by a clinician who can account for these confounders. A single FibroSure result should not be used in isolation to make major clinical decisions. Any significant change in management, such as escalation to biopsy, specialist referral, or treatment decisions, should be based on the full clinical picture including imaging, clinical examination, and relevant blood tests.

Who should consider getting a FibroSure test in the UK?

FibroSure is most relevant for adults with known or suspected chronic liver disease, including MASLD or alcohol-related liver disease, who need non-invasive fibrosis assessment, particularly when biopsy is contraindicated or declined.

People who may benefit most from FibroSure testing are those with known or suspected chronic liver disease who need a non-invasive estimate of fibrosis severity, particularly when a liver biopsy is contraindicated or declined. In the UK, the most common clinical scenarios include patients with MASLD who have risk factors such as type 2 diabetes, obesity, or metabolic syndrome, and those with alcohol-related liver disease where ongoing monitoring of fibrosis progression is clinically relevant.

NICE guidance (NG49) sets out a stepwise approach for adults with MASLD. Initial risk stratification in primary care uses FIB-4 or the NAFLD Fibrosis Score. Those identified as being at higher risk of advanced fibrosis are then assessed using the ELF test, and those with an elevated ELF score are referred to a specialist hepatology service. FibroSure is not part of this NICE-recommended primary care pathway, but may be used within specialist centres where it has been locally adopted as a complementary or confirmatory tool.

Other groups who may be considered for FibroSure testing include:

• Patients with chronic hepatitis B or C who are being assessed for treatment eligibility or monitoring

• Individuals with persistently elevated liver enzymes of uncertain cause, following initial investigation

• Those who have had a previous indeterminate liver biopsy and require ongoing non-invasive monitoring

• Patients in whom biopsy carries elevated risk, such as those on anticoagulants

It is worth noting that assessment pathways and test performance differ in children and in pregnancy, and specialist input is required in these groups. This article addresses adult assessment only.

For people exploring non-invasive liver assessment as part of a broader metabolic health review, Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online health consultations, with prescriber review and pharmacist support, where clinically appropriate pathways can be discussed. Any decision about liver investigation should involve a GP or specialist who can review the full clinical picture.

Limitations and accuracy of FibroSure in clinical practice

FibroSure has AUROC values of approximately 0.80 to 0.85 for detecting significant fibrosis but is least reliable in the intermediate range and cannot assess steatosis grade, portal hypertension, or hepatocellular carcinoma.

FibroSure performs well at the extremes of fibrosis staging but has recognised limitations in the intermediate range, which is precisely where many patients with fatty liver disease fall. Published meta-analyses report area under the receiver operating characteristic curve (AUROC) values in the region of 0.80 to 0.85 for distinguishing significant fibrosis from minimal fibrosis in chronic liver disease, though these figures vary by disease aetiology, study population, and spectrum bias. Performance in MASLD and ALD may differ from that reported in hepatitis C cohorts, where most of the original validation work was conducted. Clinicians should consult current systematic reviews and the laboratory's own interpretive documentation when applying these figures to individual patients.

A key practical limitation is that FibroSure is a proprietary test with associated laboratory costs. It is often not included in standard NHS pathways, and availability varies by ICB and local hepatology service. Patients seeking the test privately should be aware that the cost of the laboratory analysis is separate from any consultation fee, and should confirm that testing is performed by a UKAS-accredited laboratory.

FibroSure also cannot replace clinical assessment. It does not provide information about hepatic steatosis grade, portal hypertension, or the presence of hepatocellular carcinoma, all of which may be relevant in advanced liver disease. Imaging, endoscopy, and clinical examination remain essential components of a comprehensive liver assessment.

If you are concerned about symptoms that may indicate significant liver disease, such as jaundice, abdominal swelling, unexplained weight loss, vomiting blood, dark or tarry stools, or increasing confusion, contact your GP in the first instance. If symptoms are severe or rapidly worsening, seek urgent assessment via NHS 111 or attend an emergency department.

Healthcare professionals and patients should report any suspected adverse reactions to medicines or diagnostic products to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Scientific References

1. LIVERFASt for assessing and monitoring liver fibrosis (MIB317).
2. Metabolic dysfunction-associated steatotic liver disease (MASLD): assessment and management (NG49).
3. Haptoglobin testing in hemolysis: measurement and interpretation.
4. Accuracy of controlled attenuation parameter (CAP) and liver stiffness measurement by transient elastography.
5. Having a Fibroscan.

Frequently Asked Questions