Every baby is watched for jaundice in the hospital. Although nurses and physicians might notice jaundice by looking and touching your baby’s skin, other tests must be used to accurately measure the level of bilirubin. These are the serum bilirubin test and the transcutaneous bilirubin test. The serum bilirubin test is a blood test that is sent to the hospital laboratory. Blood for this test is usually taken from a small puncture of your baby’s heel. It can take an hour or longer to get the results of the serum bilirubin test. A transcutaneous bilirubin can be done with a small hand-held instrument that measures the level of jaundice through the baby’s skin. It is not an invasive procedure as it does not require any blood and the results are instantaneous. Some babies might need to have both types of bilirubin tests. If the transcutaneous bilirubin test is high, a blood bilirubin test will be done to see if treatment is necessary.