Intended Use The Immuchrom Bile Acids Assay Kit is photometric test that enables easy, rapid and precise quantitative determination of free bile acids in human stool samples. For research use only. Description Bile acids play a significant role in the absorption of lipids and fat-soluble vitamins in the small intestine, as well as in the excretion of cholesterol. Furthermore, they contribute to the stimulation of intestinal motility. Bile acids function, among other things, in the digestion of fats, are formed in the liver and released into the duodenum with the bile. In the last section of the small intestine, about 95-97% of the bile acids are reabsorbed (enterohepatic circulation). If the absorption of bile acids in the small intestine is impaired, they are increasingly excreted in the stool, which leads to irritation of the colon and causes severe diarrhea, resulting in severe fluid loss as well as vitamin and mineral deficiencies. This is called bile acid malabsorption syndrome or chologenic diarrhea. The ImmuChrom bile acids kit allows an easy, rapid and precise quantitative determination of bile acids in stool samples. The kit includes all reagents ready to use for preparation of the samples. Type Photometric assay Other names steroid carboxylic acids, cholic acid, chenodeoxycholic acid Principle of Method The quantitative determination of bile acids is carried out via their enzymatic oxidation to 3-keto steroids with the formation of thio-NADH. The resulting change in absorbance (ΔOD) at 405 nm is determined photometrically. The concentration can be calculated from the standard curve. Sample Types Stool Sample Volume Extraction in stool extraction vials The bile acids are extracted by the extraction buffer out of the stool sample. Extraction in stool extraction vials In a stool sample extraction vial mix 15 mg stool with 1.5 ml EXT, then vortex it until the mixture is homogenous. Transfer the resulting slurry to a plastic vial and centrifuge it for 10 min at 3000xg. The supernatant is directly pipetted into the microtiter plate wells with no further dilution. Standard Curve Calibration Range: 9 - 280 µmol/L Limit of Detection 1.91 µmol/L For the determination, the zero-standard was measured 12 times. The 3-fold standard deviation was added to the mean value. The respective concentration was read from the standard curve. Precision and reproducibility Intra-Assay (Within-Run) CV: 2.5 % (508 μmol/l) [n = 10] 4.7 % (2248 μmol/l) [n = 10] 10.7 % (6263 μmol/l) [n = 10] Inter-Assay (Run-to-Run) CV: 7.6 % (466 μmol/l) [n = 10] 9.9 % (1787 μmol/l) [n = 10] 13.6 % (6281 μmol/l) [n = 10] Dilution Linearity Test sample Dilution Expected Concentration (μmol/l) Measured Concentration (μmol/l) Recovery (%) 1 - - 17480 - 1 1:1.3 13539 10760 79.5 1 1:1.5 11787 8983 76.2 1 1:1.7 10448 7466 71.5 1 1:2 8941 5625 62.9 1 1:3 6095 3683 60.4 1 1:4 4671 2838 60.8 2 - - 5235 - 2 1:1.3 4120 3358 81.5 2 1:1.5 3624 2709 74.8 2 1:1.7 3245 2410 74.3 2 1:2 2818 1961 69.6 2 1:3 2013 1353 67.2 2 1:4 1610 1063 66.0 3 - - 1043 - 3 1:1.3 895 783 87.5 3 1:1.5 829 754 90.9 3 1:1.7 779 700 89.8 3 1:2 723 675 93.5 3 1:3 616 605 98.3 3 1:4 562 577 103.0 Spiking Recovery Test sample Endogenous (μmol/l) Spike (μmol/l) Expected Concentration (μmol/l) Measured Concentration (μmol/l) Recovery (%) 1 744 734 1478 1282 86.7 1 744 3670 4415 4619 105 1 744 7341 8085 7208 89.2 2 2223 1043 3266 3027 92.7 2 2223 5215 7438 6528 87.8 2 2223 10430 12653 11460 90.6 3 6175 1043 7218 6591 91.3 3 6175 5215 11390 10800 94.8 3 6175 10430 16605 15730 94.7 Storage Store the kit refrigerated at 2-8 °C. Intended Use This assay is intended for research use only and is not for use in diagnostic procedures. Resources Product Datasheet (PDS) References to Summary Neumeister, B.: Klinikleitfaden Labordiagnostik. Elsevier Urban & Fischer, München 2009 Pschyrembel. Klinisches Wörterbuch. 266. Auflage. De Gruyter, Berlin 2014 Stephen D. Turley and John M. Dietschy: Re-evaluation of the 3α-hydroxysteroid dehydrogenase assay for total bile acids in bile; Journal of Lipid Research Volume 19 Notes on Methodology 1978: 924-928 Priya Vijayvargiya, Michael Camilleri, Andrea Shin and Amy Saenger: Methods for Diagnosis of Bile Acid Malabsorption in Clinical Practice; CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2013; Vol. 11: 1232–1239 Jack L. Porter, John S. Fordtran, Carol A. Santa Ana, Michael Emmett, Lee R.Hagey, Edith A. MacDonald, and Alan F. Hofmann: Accurate enzymatic measurement of fecal bile acids in patients with malabsorption; JOURNAL OF LABORATORY AND CLINICAL MEDICINE, July 2003 (https://www.researchgate.net/publication/10696339 Related Products Alpha-1 Antitrypsin ELISA for Human Stool Anti-Gliadin sIgA / IgA ELISA for Human Stool Beta-Defensin 2 ELISA for Human Stool Calprotectin ELISA for Human Stool EDN (Eosinophil Derived Neurotoxin) ELISA for Human Stool Lysozyme ELISA for Human Stool Pancreatic Elastase ELISA for Human Stool Secretory IgA (sIgA) ELISA for Human Stool, Saliva Ilex Life Sciences LLC is an official distributor of Immuchrom GmbH.
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