Automated Jendrassik-Grof method for measurement of bilirubin in serum with the Greiner Selective Analyzer (GSA II D), and comparison with the method involving diazotized 2,4-dichloroaniline.

We automated the Jendrassik-Grof method for measurement of bilirubin with the Greiner Selective Analyzer GSA II D. Comparison with the manual Jendrassik-Grof method showed a highly significant correlation coefficient of 0.994 for total and 0.980 for "direct" bilirubin measurement. The automated method showed good precision and was linear to 667 mu mol/L, the highest concentration tested. Addition of hemolysate caused a greater effect on the measurement of direct bilirubin than on total bilirubin. The inhibitory effect on measurement of total bilirubin, though small, was statistically significant at hemoglobin concentrations greater than 2 g/L. Comparison with the method involving diazotized 2,4-dichloroaniline showed the Jendrassik-Grof method to be relatively less affected by hemolysis and turbidity in the measurement of total bilirubin.