A NEW blood test, the FAP-Index, accurately identifies serious scarring (fibrosis) in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), a 2026 retrospective cohort study has found.
Researchers found that adding the FAP-Index to first-line blood tests reduced uncertain results by up to 70% compared with the current screening tools alone.
The add-on blood test incorporates fibroblast activation protein (FAP), that plays a key role in the scarring process, using routine clinical information to give a precise assessment of fibrosis risk.
Ziqi Vincent Wang, PhD student at the Centenary Institute and the University of Syndey, Sydney, Australia, said: “Fatty liver disease is incredibly common but it’s very difficult to know who has severe liver damage.
“The FAP-Index is designed to be simple, affordable, and practical, so it can be used early in primary care to identify patients who genuinely need further investigation.”
Current Tests for Liver Fibrosis
MASLD is often asymptomatic in early stages but can progress to fibrosis and eventually liver cirrhosis and failure.
Non-invasive blood tests are currently favoured for diagnosis of advanced liver fibrosis. The two most common are nonalcoholic fatty liver disease fibrosis score (NFS) and Fibrosis Index 4 (FIB-4).
Researchers highlighted that current first-line blood test risk scores can produce indeterminate results, resulting in unnecessary referrals and costly investigation.
Fewer Indeterminate Results
Two cohorts were recruited from tertiary hepatology clinics. The training cohort was made up of 160 patients, 20% of whom had advanced fibrosis. The external validation cohort consisted of more than 330 patients, 11% with advanced fibrosis.
The FAP-Index used data relating to age, Type 2 diabetes, alanine transaminase, and ordinal cFAP to generate a more precise assessment of liver scarring.
FIB-4 followed by FAP-Index was associated with a 30% to 40% reduction in indeterminate results when compared with FIB-4 alone.
Following NFS, the FAP-Index was associated with a reduction of approximately 70% in indeterminate results compared with NFS alone.
Future Screening
Applying the FAP-Index following FIB-4 or NFS facilitated accurate risk stratification of patients with MASLD and reduced the frequency of indeterminate results without compromising negative predictive value.
Researchers proposed that the test has the potential to significantly improve how doctors identify people at risk of serious liver damage.
Professor Mark Gorrel, laboratory head at the Centenary Institute’s Centre for Cancer Innovations, Sydney, Australia, said: “With effective therapies becoming available, there is an urgent need for better tools to test patients and more accurately detect advanced fibrosis earlier.
“By focusing on a protein central to liver scarring and reducing uncertain results, the FAP-Index has the potential to ease pressure on specialist services while ensuring patients in need receive timely care.”
Reference
Wang ZV et al. A novel fibroblast activation protein-based algorithm to assess fibrosis in metabolic dysfunction-associated steatotic liver disease. JGH. 2026;doi:10.1111/jgh.70294.
Featured image: fotofabrika on Adobe Stock
