ABSTRACT.The purpose of this study was to investigate whether hyperbilirubinemia (15 mg/dl) could be predicted by TcB readings at birth or change of TcB readings during the first 24 hours of life. Both the TcB at 24 hours and the ratio of increase of TcB during the first 24 hours per kg birthweight were useful in predicting the development of hyperbilirubinemia (15 mg/dl). The test could be used as a noninvasive screening procedure to detect infants at risk for significant hyperbilirubinemia on the first day of life.