Enterohepatic circulation is essential for maintaining a constant bile acid concentration. Diseases with enterohepatic circulation disturbances are usually difficult to diagnose definitively without the time-consuming and expensive genetic tests. This study analyzed and compared duodenal fluid in patients with biliary atresia (BA), familial intrahepatic cholestasis 2 (FIC2), and sodium taurocholate cotransporting polypeptide (NTCP) deficiency. This study aimed to assess the diagnostic value of duodenal fluid analysis in patients with enterohepatic circulation disturbance. This study retrospectively analyzed data from 18 patients with BA, 13 patients with FIC2, and 15 patients with NTCP deficiency. All patients completed the duodenal tube tests before receiving treatment for cholestasis. The patients were intubated through the right nasal cavity to the middle or lower duodenum, as confirmed by radiography. 3-5 mL of duodenal fluid was collected at last. Clinical presentations, laboratory data, genetic data, and so forth were collected for the analysis. Among the 3 types of diseases, levels of total bile acid (TBA), total bilirubin (TB), direct bilirubin (DB), and gamma-glutamyl transpeptidase (GGT) in duodenal fluid showed significant differences (P <
.01). Compared with the same indications in duodenal fluid, levels of TBA and GGT in serum did not show significant differences between patients with FIC2 and NTCP deficiency (P >
.05). Duodenal TBA/serum TBA ratio, duodenal TB/serum TB ratio, duodenal DB/serum DB ratio, and duodenal GGT/serum GGT ratio also showed significant differences between patients with BA and NTCP deficiency, between patients with FIC2 and NTCP deficiency (P <
.01). For diagnosis of BA, increased GGT and absent TB, DB, and TBAs had a sensitivity of 100%, 100%, 100%, and 100%, a specificity of 86.1%, 100%, 97.2%, and 97.2%. Duodenal tube tests have been used for the diagnosis of BA for over 10 years. Our findings support the duodenal fluid analysis as a tool for prompt timely diagnosis of BA. This study also indicates that the test is a useful diagnostic method with high accuracy for other diseases with enterohepatic circulation disturbance.