Transcutaneous bilirubinometry is critical in neonatal jaundice as it provides a non-invasive, rapid, and reliable estimation of bilirubin levels. This allows early detection and monitoring of hyperbilirubinemia, preventing progression to severe jaundice and kernicterus. Unlike invasive blood sampling, it minimizes stress and risks in neonates, enabling frequent assessments to guide timely treatment decisions such as phototherapy. Thus, it is the most appropriate and practical monitoring tool in managing neonatal jaundice.

Reference: Nelson Textbook of Pediatrics, Kliegman, 21st Edition.