Determination of serum creatinine by Jaffe method and how to calibrate to eliminate matrix interference problems.
BACKGROUND
The calibration of Jaffe method for serum creatinine using one serum-based standard complemented with artificial matrix compensating standard's Jaffe-interfering substances allows two-point calibration with results well comparable with enzymatic methods.


METHODS
Spectrophotometry was used.


RESULTS
Jaffe procedures compensating serum/plasma intereferents by subtracting a constant amount of creatinine poorly overcompensate creatinine in children. Two-point calibration with a pair of primary serum standards certified by the reference measurement procedure (isotope-dilution, mass spectrometry) or with a pair of secondary standards linked to primary materials could provide results well agreeable with enzymatic determination. Such a calibration comprises an absorbance offset corresponding to other-than-creatinine Jaffe-interfering chromogens present in standards in the calibration line, while a two-point calibration combining one standard with physiological saline/water always grossly distorts calibration line. We calculated/prepared artificial serum matrices capable of compensating Jaffe-interfering chromogens in serum standards. The combination of even one standard with its artificial matrix also enables two-point calibration with practically the same results as with a pair of primary standards.


CONCLUSIONS
A two-point calibration of Jaffe method for serum creatinine combining only one serum standard with creatinine solution matching standard's allow matrix-present interferents present results well comparable with enzymatic determination, providing the standard is attested/linked to the reference measurement procedure.
Chromý
Vratislav
V
Institute of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic. vrch@chemi.muni.cz
Rozkosná
Katerina
K
Sedlák
Pavel
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D016477:Artifacts; D001663:Bilirubin / Q000378:metabolism; D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards; D002138:Calibration; D002648:Child; D003404:Creatinine / Q000097:blood*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D012015:Reference Standards; D013644:Tartrates / Q000378:metabolism; D013997:Time Factors
D013644:Tartrates; D003404:Creatinine; D001663:Bilirubin; C029768:tartaric acid