6533b835fe1ef96bd129e8ec

RESEARCH PRODUCT

Interpretation and Chemometric Evaluation of the Bilirubin Interference in the Kinetic Spectrophotometry Determination of Creatinine in Serum by Use of the Jaffe Reaction

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Abstract SUMMARY In an alkaline picrate medium we demonstrated the occurrence of isosbestic points over the range 520–550 nm, the position depending on the bilirubin content and less on the albumin content. Bilirubin does not markedly modify the ratt constant of the reaction between creatinine and picrate, however, it does modify the intercept of the Ln ΔA vs t, plots. The absolute value of Ln ΔA varies with the concentration, though not with time, which indicates that bilirubin acts by consuming part of the initially present creatinine irrespective of its owr concentration at the wavelengths typically used in the creatinine determination. The Ln ΔA values at the isosbestic points coincide with those obtained in its absence. From the results obtained by applying the Youden and Standard-Addition methods we can conclude that bilirubin gives rise to systematic errors in the creatinine determination. The magnitude of interference depends on its concentration, changing the intercept of the plots. The results o...