Newborns with this condition may appear normal at birth. However, jaundice (a yellow color to the skin and mucus membranes) develops by the second or third week of life. The infant may gain weight normally for the first month, but then will lose weight and become irritable, and have worsening jaundice.

Other symptoms may include:

• Dark urine
• Enlarged spleen
• Floating stools
• Foul-smelling stools
• Pale or clay-colored stools
• Slow growth
• Slow or no weight gain

The health care provider will perform a physical exam, which includes feeling the patient's belly area. The doctor may feel an enlarged liver.

Tests to diagnose biliary atresia include:

• Abdominal x-ray
• Abdominal ultrasound
• Blood tests to check total and direct bilirubin levels
• Hepatobiliary iminodiacetic acid (HIDA) scan, also called cholescintigraphy, to help determine whether the bile ducts and gallbladder are working properly
• Liver biopsy to determine the severity of cirrhosis or to rule out other causes of jaundice
• X-ray of the bile ducts (cholangiogram)