Reference Values of Serum and Urine Creatinine, and of Creatinine Clearance by a New Enzymatic Method

Abstract

SUMMARY. A new, totally enzymatic procedure for the determination of creatinine in serum and urine, using creatinine amidohydrolase, creatine amidinohydrolase, sarcosine oxidase and formaldehyde dehydrogenase is described. The assay was adapted to a discontinuous analyser with each analysis requiring only 20 J.lL of serum or 3 J.lL of urine. Analytical recovery of creatinine in serum and urine averaged 100· 61170. Within-run and between-run precision studies gave coefficients of variation of 1·1 % and I· 8%, respectively, for a serum with mean values of 83 J.lmollL (9' 4 mg/L) creatinine.Creatinine concentrations in serum and urine were measured by this procedure, in Japanese children and adults. The reference intervals for serum creatinine concentrations in adults 'were 55-96J.lmol/L (6'2-10'9mg/L) in men and 40-66J.lmollL (4'5-7'5mg/L) in women, and for urine, 9'46-19'0Immollday (1070-2150 mg/day) in men and 6,75-10,61 mmollday (764-1200 mg/day) in women. The reference intervals of creatinine clearance were 88· 0-176' 4 mL/min in men and 75'7-173'OmL/min in women. Additional key phrases: creatine and creatinine amidohydrolases; interference with enzymatic methodUsing our procedure, creatine is produced from creatinine by creatinine amidohydrolase (EC 3.5.2.10) and degraded to sarcosine and urea by creatine amidinohydrolase (BC 3.5.3.3). The sarcosine formed then reacts with sarcosine oxidase (BC 1.5.3.1), in the presence of formaldehyde dehydrogenase (BC 1.2.1.1) and NAD. The NADH + H+ produced is measured at 340 nm.

Determination of Creatinine in Human Urine with Flow Injection Tandem Mass Spectrometry

“…Colorimetric determinations of the picrate salt or assays based on enzymatic reactions are commonly used in clinical chemistry [11,12,13]. Creatinine assays examining the reaction of creatinine and picric acid were first reported by Jaffé [14].…”

Comparison of Simultaneous Renal Clearances of True Endogenous Creatinine and Subcutaneously Administered lothalamate in Man

“…Therefore precision is needed in order to detect a true change in function from a variability in the measurement tech nique. Previous studies using total chromogen, such as that determined by an autoanalyser, as a measure of serum and urine creatinine have suggested that creatinine clearance has a low precision [2], However, this is likely to be accounted for by the variable contribution of noncrea tinine chromogens to the creatinine assay [11,23], which in general, is relatively less of a problem at higher levels of plasma creatinine. In a study comparing the effect of interfering substances on the measurement of creatinine, 28 different laboratories routinely using 17 different methods for the determination of serum creatinine (three major variations of the alkaline picrate method and two 280 Pollock/Gyory/Hawkins/Ross/Ibcls True Creatinine versus Iothalamate Clearances enzymatic methods), assayed samples containing plasma alone, or with the addition of 55 mmol/1 glucose, or 10 mmol/1 acetoacetate or 320 pl/1 or 2 mmol/1 cefotoxin [24].…”

A rapid urine creatinine assay by capillary zone electrophoresis

“…The 24 h urine creatinine correlation with total lean body mass (LBM) has been verified [16] and the decrease in LBM association with aging results from a specific loss of muscle [17]. A 24 h urine creatinine difference between genders has been observed; men show higher values than women and it decreases with age in both genders [10,18,19]. The aim of our work was to carry out a simple, rapid, and cheap CE method to measure creatinine in extemporaneous diluted urine.…”

“…The JaffØ reaction is a method in which a creatininepicrate adduct is formed, but this assay is not completely specific because several of the urine substances form colored molecules with alkaline picrate reagent [1,2]. Other methods use chromatographic separation [3±6], ionselective electrode as well as oxygen-sensitive electrodes [7±9], and also enzymatic methods [10,11]. Some of these methods present interferences and others are expensive.…”