Alternative testing approach for a common cause of chronic diarrhea

Convenient serum test to identify bile acid malabsorption 

Chronic diarrhea and abdominal pain can be caused by many conditions, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), celiac disease, infectious GI pathogens, and malignancy. When other causes of chronic diarrhea have been excluded, a diagnosis of IBS-diarrhea (IBS-D) should be considered. One main cause of IBS-D is bile acid malabsorption (BAM).

Affecting 25% to 30% of IBS-D patients1, BAM occurs when an individual is unable to reabsorb bile acids released into the small intestine during digestion. Identifying patients affected by BAM is traditionally done by measuring total and fractionated bile acids in stool through timed fecal collection.

Less-invasive test provides actionable results

Because the loss of bile acids in the stool of individuals affected by BAM leads to upregulation of bile acid synthesis in the liver, serum concentrations of the metabolic intermediate in bile acid synthesis, or 7α-hydroxy-4-cholesten-3-one (7AC4), will become elevated. Measuring serum 7AC4 concentration can be used in place of timed fecal collection.2-4

Results of Mayo Clinic Laboratories’ stand-alone 7AC4 serum screening not only provide physicians with a clearer understanding of the likelihood of BAM, but help to make informed decisions for patient follow-up, including the need for confirmatory fecal testing or the benefit of a trial bile acid sequestrant treatment.

Key testing

Learn more about how to order these evaluations at your institution.


  1. Aziz I, Mumtaz S, Bholah H, et al. High prevalence of idiopathic bile acid diarrhea among patients with diarrhea-predominant irritable bowel syndrome based on rome iii criteria. Clin Gastroenterol Hepatol. 2015;13:1650–5 e2.
  2. Vijayvargiya P, Camilleri M, Shin A, et al. Methods for diagnosis of bile acid malabsorption in clinical practice. Clin Gastroenterol Hepatol. 2013;11(10):1232-1239.
  3. Camilleri M, Nadeau A, Tremaine WJ, et al. Measurement of Serum 7 Alpha-hydroxy-4-cholesten-3-one (or 7AC4), a surrogate test for bile acid malabsorption in health, ileal disease and irritable bowel syndrome using liquid chromatography-tandem mass spectrometry. Neurogastroenterol Motil. 2009;21(7):734-743.
  4. Wong BS, Camilleri M, Carlson P, et al. Increased bile acid biosynthesis is associated with irritable bowel syndrome with diarrhea. Clin Gastroenterol Hepatol. 2012 Sep;10(9):1009-1015.e3.