A Robust Procedure for the Automated Measurement of Total Serum Bilirubin Using Potassium Ferricyanide

Abstract
Bilirubin is oxidized to biliverdin by 1·0 mmol/L potassium ferricyanide in the presence of caffeine. The absorbance decline at 480 nm with blanking at 660 nm is proportional to bilirubin concentration. The assay is linear up to 1000μmol/L and is suitable for the measurement of bilirubin in adult and neonatal patients. The assay is accurate and precise and is not significantly affected by haemolysis up to 5·0 g/L haemoglobin. Reagents and calibration are stable for at least 3 months.