Serum C4 threshold for bile acid diarrhea

What is known

• The 48.3 ng/mL cutoff had 90.9% sensitivity, 84.4% specificity and AUROC 0.94 across all patients; BAD was present in 50% above vs 1.8% below the threshold. ¹
• Restricted to patients presenting with diarrhoea, the same cutoff performed better (AUC 0.99, 90.9% sensitivity, 95.5% specificity) for identifying low FGF19. ¹
• A separate pediatric IBD study used a different normal limit of 66.5 ng/mL for C4. ²

What is unknown / caveats

• Adult threshold 48.3 ng/mL vs a 66.5 ng/mL normal limit cited in a pediatric IBD study
• Single 2019 retrospective cohort, authors state prospective validation is needed
• Derived within a Crohn's/ileal-resection population, not a general population
• Reference standard was FGF19 <60 pg/mL, not SeHCAT
• The 48.3 ng/mL cutoff comes from one unvalidated cohort and may not generalise beyond Crohn's disease.

References

1. Battat R, Duijvestein M, Vande Casteele N, Singh S, Dulai PS, Valasek MA, Mimms L, McFarland J, Hester KD, Renshaw M, Jain A, Sandborn WJ, Boland BS. Serum Concentrations of 7α-hydroxy-4-cholesten-3-one Are Associated With Bile Acid Diarrhea in Patients With Crohn's Disease. Clin Gastroenterol Hepatol. 2019;17(13):2722-2730.e4. PMID: 30448597.

2. Gothe F, Beigel F, Rust C, Hajji M, Koletzko S, Freudenberg F. Bile acid malabsorption assessed by 7 alpha-hydroxy-4-cholesten-3-one in pediatric inflammatory bowel disease: correlation to clinical and laboratory findings. J Crohns Colitis. 2014;8(9):1072-8. PMID: 24666974.

For educational use only, not a substitute for clinical judgement or medical advice. Consult qualified clinicians for diagnosis and treatment decisions. This tool may contain errors; use the flag button below to report inaccurate or harmful content.

Draft, generated by the IBDology RAG and not yet clinician-reviewed. Answers are grounded in the retrieved literature listed above; a high faithfulness score means the answer matches its sources, not that the sources are correct.