Infants with biliary atresia usually appear healthy at birth. Most often, symptoms develop within the first two weeks to two months of life. The majority of children with jaundice undergo a series of tests to distinguish biliary atresia from other conditions.

1. Physical Exam
Your doctor will perform a physical exam and will look for or ask questions about the following: jaundice; dark urine; light or pale colored stools; distended abdomen; poor weight gain.

2. Blood Tests
A variety of blood tests can be used to assess liver function. They include:

__Liver enzyme tests (AST, ALT, GGT) - Elevated levels of liver enzymes can alert physicians to liver damage or injury, since the enzymes leak from the liver into the bloodstream under these circumstances.

__Bilirubin - Bilirubin is produced by the liver and is excreted in the bile. Elevated levels of direct or conjugated bilirubin often indicate an obstruction of bile flow or a defect in the processing of bile by the liver.

__Albumin, total protein, and globulin - Below-normal levels of proteins made by the liver are associated with many chronic liver disorders.

__Clotting studies, such as prothrombin time (PT) and partial thromboplastin time (PTT) - Tests that measure the time it takes for blood to clot may be used to diagnose biliary atresia. Blood clotting requires vitamin K and proteins made by the liver. Liver cell damage and bile flow obstruction can both interfere with proper blood clotting.

__Infectious, genetic and metabolic studies - Tests on sweat, blood and urine may be done to look for other causes of liver problems that sometimes look very similar to biliary atresia.

3. Radiology Tests
Abdominal ultrasound - a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.

Abdominal computerized tomography scan (also called CT or CAT scan) - a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called "slices"), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed than general X-rays.

DISIDA or HIDA scan - a diagnostic imagining technique which uses an injected radioactive dye to determine whether there is bile flow from the liver into the gallbladder and intestines.

4. Liver Biopsy
A tissue sample is taken from your child's liver and examined for abnormalities, allowing biliary atresia to be distinguished from other liver problems.
Operating room diagnosis

In some cases, a cholangiogram is performed in the operating room. This is an X-ray imagining study performed by a surgeon in the operating room to determine if there is blockage of bile flow in the ducts leaving the liver.