Are there specific biomarkers that can accurately diagnose ulcerative colitis in a new patient?
Diagnosing ulcerative colitis (UC) typically requires a colonoscopy with biopsy, which is invasive and uncomfortable. Researchers are actively looking for biomarkers—measurable substances in blood or stool—that could diagnose UC more easily. A 2025 study identified three specific biomarkers that accurately distinguish UC from healthy individuals and from Crohn's disease. Other research points to bile acid ratios in blood and stool as potential noninvasive markers for UC activity.
What the research says
A 2025 study integrated multiple datasets and used machine learning to identify three biomarkers—ARHGEF3, S100A8, and RHOU—that showed excellent diagnostic performance for UC. The diagnostic model achieved an AUC (a measure of accuracy) of 0.991 in the training set and 0.938–0.968 in external validation cohorts 6. These biomarkers also helped differentiate UC from Crohn's disease 6.
Another 2025 study examined bile acid profiles in serum and fecal samples from UC patients and healthy controls. It found that reduced serum deoxycholic acid (DCA)/cholic acid (CA) ratio and increased fecal ursodeoxycholic acid (UDCA)/chenodeoxycholic acid (CDCA) ratio were associated with UC disease activity. These bile acid ratios were highly accurate in predicting active versus remission stages 9.
While these biomarkers are promising, they are not yet standard clinical tests. A 2020 review highlighted the potential of noncoding RNAs as biomarkers for pediatric IBD, but this area is still emerging 10. The sources do not indicate that any single biomarker is currently used alone for diagnosis; instead, combinations of biomarkers and clinical assessment are likely needed.
What to ask your doctor
- Are tests for biomarkers like ARHGEF3, S100A8, or RHOU available to help diagnose my condition?
- Could a bile acid ratio test (serum or fecal) provide information about my disease activity?
- What is the role of noninvasive biomarkers versus colonoscopy in my diagnosis and monitoring?
- Are there any ongoing studies or clinical trials using these new biomarkers that I might join?
This question is drawn from common patient questions about Gastroenterology and answered using cited medical research. We do not provide individualized advice.