Indocyanine green faecal excretion holds potential for diagnosis of neonatal biliary atresia.

Aim of the study: This study aimed to establish an objective, simple, and minimally invasive screening method to detect patients with biliary atresia during neonatal checkups by using indocyanine green (ICG) fluorescence in the stool.

Material and methods: We produced a rat model of extrahepatic biliary obstruction (group O, n = 9) and compared the stools from these rats with those of control group rats (group C, n = 6) by a fluorescence technique. ICG was administered (0.5 mg/kg) through the caudal vein; group O received ICG at the end of surgery.

Results: In group C, we collected stools at 3, 6, 12, 24, 48, and 72 hours, and fluorescence disappeared at 48 hours. In group O, stools were collected at 24, 48, 72, 96, and 120 hours after surgery, and fluorescence continued at 120 hours without the loss of fluorescence. Quantitative assessment of lightness showed significant differences between the groups at 48 and 72 hours (p = 0.0016 and p = 0.0004, respectively).

Conclusions: This study shows that ICG is excreted into the gastrointestinal tract via a route other than the bile duct in a rat model of extrahepatic biliary obstruction. Our findings also suggest that ICG has the potential for initial screening of biliary congestive disease in the neonatal period, which could be followed up by detailed testing.