This is a report which is measuring bilirubin which is a substance which is a toxin and is excreted by the liver. The liver maintains the levels at a non toxic level. In very young babies the liver is still immature and hence may not be able to excrete this fast enough. The doctor must have advised this to ascertain if your baby has jaundice as the symptoms of high bilirubin is jaundice and yellow skin. You may be asked to keep the baby under bili lights. Some natural ways are frequent feeding as that washes the bilirubin out thru the urine. Also exposing the babies skin to morning sunlight can also help.