Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Mayo Clinic, Rochester, Minnesota.
Clin Gastroenterol Hepatol. 2013 Oct;11(10):1232-9. doi: 10.1016/j.cgh.2013.04.029. Epub 2013 May 2.
Altered concentrations of bile acid (BA) in the colon can cause diarrhea or constipation. More than 25% of patients with irritable bowel syndrome with diarrhea or chronic diarrhea in Western countries have BA malabsorption (BAM). As BAM is increasingly recognized, proper diagnostic methods are needed to help direct the most effective course of treatment for the chronic bowel dysfunction. We review the methodologies, advantages, and disadvantages of tools that directly measure BAM: the (14)C-glycocholate breath and stool test, the (75)selenium homotaurocholic acid test (SeHCAT), and measurements of 7 α-hydroxy-4-cholesten-3-one (C4) and fecal BAs. The (14)C-glycocholate test is laborious and no longer widely used. The (75)SeHCAT has been validated but is not available in the United States. Measurement of serum C4 is a simple and accurate method that can be used for most patients but requires further clinical validation. Assays to quantify fecal BA (total and individual levels) are technically cumbersome and not widely available. Regrettably, none of these tests are routinely available in the United States; assessment of the therapeutic effects of a BA binder is used as a surrogate for diagnosis of BAM. Recent data indicate the advantages to studying fecal excretion of individual BAs and their role in BAM; these could support the use of the fecal BA assay, compared with other tests. Measurement of fecal BA levels could become a routine addition to the measurement of fecal fat in patients with unexplained diarrhea. Availability ultimately determines whether the C4, SeHCAT, or fecal BA test is used; more widespread availability of such tests would enhance clinical management of these patients.
结肠中胆汁酸（BA）浓度的改变可导致腹泻或便秘。在西方国家，超过 25%的腹泻型肠易激综合征或慢性腹泻患者存在胆汁酸吸收不良（BAM）。随着 BAM 的认识不断提高，需要适当的诊断方法来帮助确定针对慢性肠功能障碍的最有效治疗方案。我们综述了直接测量 BAM 的方法学、优缺点：（14）C-甘氨胆酸呼吸和粪便试验、（75）硒同型牛磺胆酸试验（SeHCAT）和 7α-羟基-4-胆甾烯-3-酮（C4）和粪便 BA 的测量。（14）C-甘氨胆酸试验繁琐，不再广泛应用。（75）SeHCAT 已得到验证，但在美国不可用。血清 C4 测量是一种简单而准确的方法，可用于大多数患者，但需要进一步的临床验证。测定粪便 BA（总量和个体水平）的分析方法技术繁琐，且未广泛应用。遗憾的是，这些检测在美国都未常规应用；BA 结合剂治疗效果的评估可作为 BAM 诊断的替代方法。最近的数据表明，研究粪便中个体 BA 的排泄及其在 BAM 中的作用具有优势；与其他试验相比，这些数据可支持使用粪便 BA 分析。在不明原因腹泻患者中，粪便 BA 水平的测量可能成为粪便脂肪测量的常规附加项目。可用性最终决定了 C4、SeHCAT 或粪便 BA 试验的应用；这些检测的更广泛应用将增强对这些患者的临床管理。
