Interferences in current methods for measurements of creatinine

Abstract

We measured the interference of carbonyl compounds, drugs, and other substances in human serum on the determination of creatinine by the two-point, fixed-time kinetic modification of the Jaffé reaction as well as by four enzymatic methods. We added known concentrations of the interfering substances to a solution of creatinine in water. For bilirubin, we used both pooled normal sera with added bilirubin and icteric patient sera. The magnitude of interferences varies widely from method to method. Carbonyl compounds, dopamine, cephalosporines, and bilirubin interfere with the Jaffé reaction. Bilirubin, creatine, dopamine, ascorbic acid, and sarcosine interfere with the enzymatic methods. We conclude that the elimination of interferences in the determination of creatinine has still not been achieved.

The influence of ketoacids on plasma creatinine assays in diabetic ketoacidosis

“…This is in accordance with earlier laboratory studies in which b-hydroxybutyrate did not cause interference in the alkaline picrate method [2,4,11]. One laboratory study showed that each mmol L 21 of glucose caused a positive error of 0.3±0.4 mmol L 21 of creatinine, which is similar to the estimation in our multivariate analysis [23].…”

“…At presentation of DKA, the range of acetoacetate concentration was 1.3±5.1 and 3.6±3.9 mmol L 21 , respectively, in the two mentioned examples. The interference was greater than expected from laboratory studies using spiked' samples up to 20 mmol L 21 acetoacetate and from our own in vitro experiment [17,18,20,23]. This can be due to acetone in the patient sample.…”

“…Most of them were published in the 1970s, before the introduction of kinetic modifications of this assay. Later studies on the kinetic assay showed contradictory results of acetoacetate interference, probably due to the different lag-times between addition of the last reagent and the absorbance measurement of creatinine concentration [11±17, 23,26]. The enzymatic assay was shown not to have any interference from acetoacetate [17,18,20,23].…”

Negative interference of icteric serum on a bichromatic biuret total protein assay

“…A bilirubin stock solution of 400 mg/dL was prepared by dissolving 40 mg of bilirubin powder (Sigma-Aldrich, St. Louis, MO, USA) in 10 mL of 0.1 M sodium hydroxide (NaOH). 5,6 Serial dilutions of the bilirubin stock solution with 0.1 M NaOH were mixed with constant proportions of sera (1 part bilirubin solution + 9 parts serum) to create bilirubin concentrations between 1 and 40 mg/dL (17 and 684 lmol/L) in the first set of spiked sera, and between 4 and 35 mg/dL (68 and 598 lmol/L) in the second set of spiked sera. The first set of spiked sera was assayed to document the interference; the second set was assayed to confirm findings of the first set, and to explore the reason for the interference.…”

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

“…Plasma creatinine concentration was successively determined on the Vitros analyzer and the Olympus AU2700 analyzer, using three reagents in the same assay: Olympus-Jaffe´and two enzymatic commercial kitsFCrea Plus and Enzymatic Creatinine. The Jaffe´kinetic method is known to be subject to several interferences and poor specificity (1)(2)(3)(4). In addition, the commonly used Jaffe´and modified Jaffe´reaction methods systematically overestimated creatinine by 20% compared to enzymatic methods (5).…”