A bilirubin of 17 ina 4 day old is a not very notable, but at 4 weeks it is a
bit more unusual, and should be evaluated further. If it is all indirect, it
is probably true breast milk jaundice, and these babies can have bilirubins at
the 20-30 level for a few months without reports of kernicterus. 48 hours of
formula is said to be one way of ruling in breast milk jaundice. I think it
would be more important to "rule out" liver disease, and make sure that the
direct bilirubin is low and the baby does not have biliary atresia or neonatal
hepatitis.
By 4 weeks I feel better if I can see the whites of their eyes and this baby
is probably markedly yellow.
Mary Murphy MD