Determination of Serum Bilirubin Concentration during Phototherapy of Newborns and In Vitro: Results Compared by the Direct Spectrometric Method and the Diazo Method

Abstract

During direct illumination of a serum bilirubin solution the bilirubin concentration decreased markedly, both as de-termined by the direct spectrometric method and (even more so) by the diazo method. In contrast, I found the same values for serum bilirubin concentrations as determined by these two methods for serum from untreated, "single light," and "double light" treated full-term infants with neonatal hyperbilirubinemia without blood type immuni¬zation. The same was true for untreated and "single light" treated premature infants with this disease. Furthermore, no difference was found in the above-mentioned rela¬tionship between "single light" treated infants with rhesus hemolytic disease, "double light" treated infants with the same disease, and untreated infants with neonatal hyp¬erbilirubinemia without immunization, all born at term. This is important, because the direct spectrometric method is simpler and requires less serum than does the diazo method