Albumin binding properties in relation to bilirubin and albumin concentrations during the first week of life.

In 19 non-jaundiced and 22 jaundiced neonates, the serum albumin and bilirubin concentrations were measured during the first week of life. Some of the neonates were followed longitudinally. The albumin binding properties were evaluated by determining the reserve albumin concentration for monoacetyldiaminodiphenyl sulphone (MADDS), a deputy ligand for bilirubin. The reserve albumin concentration for MADDS increased with postnatal age. The reason for this increase is still unexplained. There was an inverse relation between the bilirubin and the reserve albumin concentrations, but when the bilirubin concentration increased by 1 mumol/l, the reserve albumin concentration for MADDS decreased by only 0.2 mumol/l. This shows that the reserve albumin concentration for MADDS does not give a direct measure of the bilirubin binding ability of the serum albumin molecule. In spite of this, it is still possible that a low reserve albumin concentration for MADDS is a risk factor for bilirubin encephalopathy.