Realization of the total and direct reaction of ditaurobilirubin via the use of a modified Jendrassik-Grof diazo procedure

Currently, the diazo method is globally accepted as a reference measurement procedure (RMP) for total bilirubin (TBIL) quantitation. However, the lack of an RMP and reference materials for the quantitation of direct-reacting bilirubin (DBIL) has necessitated the use of unconjugated bilirubin (UCB) as a calibrator for DBIL assaying. In such measurements, the calibrator (UCB) must be analyzed by a procedure employed for TBIL in the presence of an accelerator that renders UCB watersoluble and diazo-positive. Recently, ditaurobilirubin (DTB), a synthetic water-soluble bilirubin derivative that directly reacts