Investigations into negative interference by jaundiced plasma in kinetic Jaffé methods for plasma creatinine determination.

Negative interference by jaundiced plasma in kinetic Jaffé methods for plasma creatinine determination is caused by both conjugated and unconjugated bilirubin. The amount of interference observed is method- and temperature-dependent and is directly related to bilirubin concentration but is independent of the creatinine concentration. Bilirubin also significantly reduces the precision of the creatinine estimation. A mechanism of bilirubin interference in kinetic Jaffé methods is proposed and the influence of picrate concentration, hydroxide concentration and temperature on the magnitude of bilirubin interference has been investigated.