Serum delta bilirubin estimation by an automated method.

This study compares delta bilirubin values in 40 serum samples from patients with various diagnoses, as estimated by the automated Kodak Ektachem system and measured by a manual method. Regression analysis of the results yielded a slope = 0.832, intercept = 9.9 and r = 0.724. Within-run standard deviation was 1.7 mumol/l for the automated method. In samples with predominantly unconjugated bilirubin, the Ektachem system over-estimated delta bilirubin values. In specimens with conjugated hyperbilirubinaemia, the Ektachem system and manual method were in close agreement for delta bilirubin values. We conclude that samples with predominantly unconjugated bilirubin should have the presence of delta bilirubin confirmed by the manual assay. Since the Ektachem system currently provides the only automated means of estimating delta bilirubin values, its use appears warranted.