75Se-Homocholic acid taurine scintigraphy (75SeHCAT®), a standard benchmark test in bile acid malabsorption?

Chronic diarrhoea due to bile acid malabsorption (BAM) is an underdiagnosed pathology. Different diagnostic tools are available. However, there is currently no consensus on which of these would be the benchmark test or gold standard. This review evaluates the possibility of using 75Se-taurocholic acid (75SeHCAT®) scintigraphy as a benchmark diagnostic test and its perspective for the future. A literature review was conducted in Pubmed and OVID obtaining a total of 57 papers, 26 of which were finally used after being selected under the concepts of gold standard, diagnostic accuracy and other biomarkers. We evaluated the advantages and disadvantages of the different diagnostic tools: 14C-glycocholate, measurement of bile acids in faeces, C4 in serum, FGF19 in serum, cholestyramine, and 75Se-tauroselcolic acid scintigraphy. We consider that the 75SeHCAT® scan is the most recommended diagnostic test in Europe for diagnosing BAM as it presents the highest values of sensitivity and specificity. It has a significant cost-benefit ratio, making it the test with the highest degree of recommendation. However, it is still not possible to use it in a recognised way as a gold standard due to the lack of studies that provide conclusive data that allow consensus. In the meantime, the combined use of cholestyramine testing in all patients we want to evaluate, regardless of the scintigraphy result, could be encouraged as a benchmark standard.