Résumé
Background: New ID-MS traceable creatinine kits including enzymatic creatinine (e-creat) and compensated Jaffe (j-creat) has been developed by Olympus.
Methods: Analytical performances of these reagents were tested on an AU (R) 640 analyzer. A comparison study was performed against the method used in our laboratory (Randox (R) creatinine enzymatic). Values of the glomerular filtration rate estimated (eGFR) from ID-MS traceable equation were compared to the GFR measured (mGFR) by a reference isotope method in a kidney transplant cohort.
Results: Total intra- and inter-assay variation coefficients were below 4 %. Creatinine values were correlated with the Randox (R) enzymatic method (e-creat = 0.98 Randox - 0.48 and j-creat = 0.99 Randox - 1.44, r(2) = 0.98). Values of eGFR obtained with both e-creat and j-creat were well correlated to mGFR in our population of renal transplants.
Conclusions: The new ID-MS traceable methods improved estimation of GFR by predictive equations. However, the limitation of the Jaffe method in specific populations such as paediatric and elderly patients needs further investigations. (Clin. Lab. 2011;57:357-361)