Does hemolysis cause a false high bilirubin ? what can cause a false low pku result

Yes: Hemolysis causes high bilirubin but it is not false. It is the breakdown of the red blood cells. A false negative can come about if a baby is tested before eating enough protein. This means the baby has phenylketonuria, but simply has not consumed enough protein for the level of phenylalanine to be high.

Confusing questions: Hemolysis will not affect the bilirubin test but may eventually lead to a higher bilirubin level when the liver processes the hemolysed cells.This is common if a newborn has a big blood pocket called a cephalohematoma under the scalp at birth.If a newborn is tested before they have had enough dietary protein (feeding) to process, the PKU test can be falsly low.Most states repeat it at 2 wks