Transcutaneous bilirubinometry: effect of postnatal age.

The purpose of this study was to determine whether the postnatal age might affect the accuracy and reliability of transcutaneous bilirubin measurements. A total of 576 transcutaneous bilirubin measurements were performed on 336 Japanese full-term breast-fed newborn infants during the first 12 days of life. We divided them into three groups according to postnatal age and studied the effect of postnatal age on the accuracy and reliability of TcB measurements. Our study revealed that the most reliable site for transcutaneous bilirubin measurements changed from the forehead to the sternum with advancing postnatal age (i.e. forehead for 0-3 days, chest for 4-5 days, sternum for 6 days and later).