Comparison between the enzymatic vitros assay for creatinine determination and three other methods adapted on the olympus analyzer

Abstract

To evaluate the relationship between the enzymatic Vitros assay for creatinine determination and other methods, we determined creatinine concentration in 400 heparin samples. Plasma creatinine level was successively determined on the Vitros 750 analyzer (Johnson & Johnson Co., Rochester, NY) and on the Olympus AU2700 analyzer (Olympus France, Rungis, France), using three reagents in the same assay: Olympus-Jaffé and two enzymatic commercial kits-Crea Plus (Roche Diagnostics, Meylan, France) and Enzymatic Creatinine (Randox, Mauguio, France). Comparison of Jaffé and enzymatic measurements of plasma creatinine levels revealed a high correlation when considering all values ranged from 20-1000 micromol/l (r > 0.99). However, for values <60 micromol/l, enzymatic reagents provided best results. Enzymatic methodology is a better clinical choice for the accurate measurement of creatinine, especially for neonates, pediatrics, and hematology units. Because analytical performance and the costs of Randox creatinine were satisfactory for our laboratory, this method, adapted on the Olympus analyzer, was chosen for routine determination of creatinine levels. According to the Valtec protocol (8), no interferences such as hemolysis, lipemia, or bilirubin were detected for Enzymatic Creatinine Randox.

The evaluation of renal function and disease in patients with cirrhosis

“…Significant inter-laboratory variations may be observed in the dosage of creatinine, mainly due to an interaction with bilirubin [16,17]. Routine creatinine dosage is based on spectrophotometry.…”

Essentials of laboratory medicine for the nephrology clinician

“…The sieving coefficient could be easily corrected if an enzymatic assay was used to measure GFR estimation using isotope dilution mass spectrometry (IDMS)-traceable calibration for serum creatinine serum creatinine, which is not influenced by bilirubin. Although there is a strong correlation between creatinine measurements by kinetic Jaffe and enzymatic assays, enzymatic assays perform better than the Jaffe method, especially for serum creatinine values <0.67 mg/dl, and thus appear to be especially useful in newborns and children [13,14].…”

Kidney Failure and Liver Allocation: Current Practices and Potential Improvements

“…Second, serum bilirubin, often elevated in patients with decompensated cirrhosis, can interfere with creatinine measurement resulting in inaccurately low creatinine values. 15 Third, the assays for creatinine measurement themselves can lead to significant discrepancies in reported creatinine values, resulting in clinically significant variation in MELD scores. 16 …”

“…15,17 For example, the Jaffe reaction is a commonly used assay that is susceptible to interference from high bilirubin levels (≥10 mg/dL), resulting in falsely low serum creatinine readings. 18 On the other hand, enzymatic colorimetric reaction has been shown to remain accurate in the setting of hyperbilirubinemia.…”