Document Detail


Predictive, error-compensating kinetic method for enzymatic quantification of creatinine in serum.
MedLine Citation:
PMID:  1868593     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Here we describe an error-compensating kinetic-based method for the enzymatic quantification of creatinine in serum. The method, which has a large linear range and very low dependency on experimental variables that influence enzyme activity, is based on the use of creatinine amidohydrolase in a four-step coupled reaction sequence to generate a product that is monitored photometrically. We collected data for absorbance vs time during two to four half-lives of each reaction and fit a first-order model to the data to compute the total absorbance change that would be measured if the reaction were monitored to completion. Computed values of absorbance change agreed well with measured values and varied linearly with creatinine concentration in the sample throughout the range examined: 44 to 1326 mumol/L. A twofold change in enzyme activity in the final reaction mixture (3.3 to 6.6 kU/L) produced changes of only 12% and 4% for creatinine concentrations of 44 and 353 mumol/L, respectively. Results (y) for 39 serum samples that contained creatinine concentrations between 20 and 1800 mumol/L agreed well with liquid-chromatographic results (x), yielding linear least-squares statistics of y = (1.03 +/- 0.01) x + (5 +/- 5) mumol/L (r = 0.995, Sy.x = 37 mumol/L). We conclude that the predictive kinetic approach is a robust method for the quantification of creatinine in serum.
Authors:
B L Bacon; H L Pardue
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Clinical chemistry     Volume:  37     ISSN:  0009-9147     ISO Abbreviation:  Clin. Chem.     Publication Date:  1991 Aug 
Date Detail:
Created Date:  1991-09-19     Completed Date:  1991-09-19     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9421549     Medline TA:  Clin Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1338-44     Citation Subset:  IM    
Affiliation:
Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393.
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MeSH Terms
Descriptor/Qualifier:
Chromatography, High Pressure Liquid
Creatinine / blood*
Enzymes / diagnostic use*
Humans
Kinetics
Predictive Value of Tests
Spectrophotometry, Ultraviolet
Grant Support
ID/Acronym/Agency:
GMS 13326-22,23/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Enzymes; 60-27-5/Creatinine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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