Diagnose suspected IBS-D

The clearest understanding of whether bile acid malabsorption is the cause of chronic diarrhea in a patient is achieved through 48-hour fecal bile acid testing, which quantifies the total bile acid in stool.

Key testing

• BA48F | Bile Acids, Bowel Dysfunction, 48 Hour, Feces

Advantages

• Offers definitive diagnosis of patients suspected of IBS-D due to bile acid malabsorption.
• Can be ordered at the same time and on the same sample as fecal fat analysis.

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Combination BAM panel

For patients who cannot tolerate the necessary preparation and collection process for fecal bile acid testing, we offer a less-invasive combination test that links fasting 7AC4 serum testing with a random, or spot stool collection. Exclusively available at Mayo Clinic Laboratories, the bile acid malabsorption panel offers an ideal collection scenario by enabling fasting serum collection during the patient’s medical visit with either at-home or in-clinic spot stool collection that is returned to the laboratory.

Key testing

• BAMRP | Bile Acids Malabsorption Panel, Serum and Feces

Advantages

• Provides 95% specificity and 66% sensitivity for the diagnosis of bile acid diarrhea.²
• Does not require patient preparation (i.e., high-fat diet or long-term collection).
• Easier on patients by allowing for fasting serum testing at medical encounter and at-home or in-clinic spot stool collection.

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Bile acid screening

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 7AC4 will become elevated. Measuring serum 7AC4 concentration can be used as a screening test when stool testing is not possible.^3-5

Key testing

• 7AC4 | 7AC4, Bile Acid Synthesis, Serum

Advantages

• Easy collection.
• Results provide physicians with a clearer understanding of the likelihood of BAM.
• Facilitates informed decision-making for patient follow-up, including the need for confirmatory fecal bile acid testing or the benefit of a trial with bile acid sequestrant treatment.

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References

1. Vijayvargiya P, Gonzalez Izundegui D, Calderon G, Tawfic S, Batbold S, Camilleri M. Fecal bile acid testing in assessing patients with chronic unexplained diarrhea: implications for healthcare utilization. Am J Gastroenterol. 2020; 115(7), 1094–1102.
2. 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.
3. Vijayvargiya P, Camilleri M, Taylor A. Busciglio I, Loftus E, Donato L. Combined fasting serum C4 and primary bile acids from a single stool sample to diagnose bile acid diarrhea. Gastroenterology. 2020;159:1n92-1954.
4. 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.
5. 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.
6. 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.
7. Borup C, Vinter-Jensen L, Jorgensen S, et al. Efficacy and safety of colesevelam for the treatment of bile acid diarrhoea: a double-blind, randomised, placebo-controlled, phase 4 clinical trial. Lancet Gastroenterol Hepatol. 2023 Apr;8(4):321-331.