Normal physiologic carboxyhemoglobinemia of neonate masquerading as carbon monoxide poisoning.

Carbon monoxide toxicity is a common concern in emergency departments. This case report describes a neonate with a falsely elevated carboxyhemoglobin level, initially raising concern for carbon monoxide exposure. The neonate was transferred to a tertiary care hospital and admitted, with hyperbaric oxygen therapy considered. Ultimately, it was determined that actual carbon monoxide exposure was unlikely, and the elevated carboxyhemoglobin was attributed to natural breakdown of fetal hemoglobin by heme oxidase. This case highlights the importance of considering this physiological phenomenon when evaluating elevated carboxyhemoglobin levels in neonates. Recognizing this led to the deferral of hyperbaric oxygen therapy, reducing unnecessary resource utilization and preventing undue stress for the family.