[Transcutaneous evaluation of icterus in healthy mature newborn infants. A substitution for blood tests].

The conventional determination of plasma bilirubin concentration in the icteric mature healthy newborn infants may frequently be replaced by transcutaneous assessment. Depending on the desired exactitude and the prevailing consensus on plasma bilirubin determination it is possible to halve the necessary number of blood tests. However, the yellow colour of the skin is influenced by several factors. Thus, transcutaneous measurements of the plasma bilirubin concentration are inaccurate. The yellow colour of the skin should be considered as an important parameter which, at least theoretically, provides information concerning the risk of bilirubinencephalopathy beyond the mere relationship to the plasma bilirubin concentration. Introduction of the method as a test of hyperbilirubinaemia requires taking a stand on several practical circumstances, determination of a standard curve with the risk of selection borne in mind and the establishment of cut-off levels.