Final answer:
The nurse should report elevated bilirubin levels to the provider as this can lead to significant health issues like jaundice and brain damage in newborns.
Step-by-step explanation:
A nurse reviewing laboratory results of a newborn who is 4 hours old should report elevated bilirubin levels to the provider. It is crucial for meconium to be cleared from the intestines and for bilirubin to be kept low in the circulation. A high concentration of bilirubin in the blood can cause jaundice, and if it reaches a high level, it can lead to brain damage due to its neurotoxicity, in a condition referred to as hyperbilirubinemia. Newborns with hyperbilirubinemia often require medical attention and are treated with phototherapy to break down the bilirubin. In contrast, the presence of meconium in stool is expected, the absence of phosphatidylglycerol may be a concern for lung maturity but is not as immediately critical as bilirubin levels, and a normal respiratory rate is a positive finding that likely needs no reporting.