Urinary sulfated bile acid analysis for the early detection of biliary atresia in infants

Background: Measurement of urinary sulfated bile acid (USBA) is a non-invasive method to detect bile congestion. Our aim was to evaluate the feasibility of USBA analysis for the early detection of biliary atresia (BA). Methods: We determined the USBA-to-creatinine ratio (USBA/cr) in 1148 infants at 10–40 days after birth. All infants were followed until the 3- to 4-month postnatal routine health check. The cutoff value for USBA/cr was 55.0 µmol/g creatinine. Results: Among the infants tested, 47 (4.10%) had USBA/cr ratios that exceeded the cutoff value. Two of these 47 infants had liver disease; one was diagnosed with neonatal hepatitis syndrome, and the other was diagnosed with BA. The BA patient underwent USBA analysis for the first time on day 18 after birth and hepatoportoenterostomy on day 49. No other infants were diagnosed with hepatobiliary disease during the follow-up period. Conclusion: This USBA analysis provided the correct assessment without fail and identified a case of BA. This approach could be used for the screening and early detection of BA when the false-positive rate is decreased by improving the methods for sample collection and urine storage.