Creatinine measurement proficiency testing: assignment of matrix-adjusted ID GC-MS target values
Anna Carobene,Carlo A. Ferrero,Ferruccio Ceriotti,A. Modenese,Marco Besozzi,Elena De Giorgi,M. Franzin,Carlo Franzini,Marzia Galli Kienle,Fulvio Magni +9 more
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TLDR
The majority of the lyophilized materials showed a behavior divergent from the frozen pools, indicating matrix-related problems, and a new algorithm for calculating matrix bias correction factor instrument-reagent specific for each material is proposed.Abstract:
The results of an external quality-assessment experiment for serum creatinine measurement are described. Fifty-one laboratories performed quintuplicate analyses during three different analytical runs on six lyophilized sera and two frozen human serum pools. Isotope dilution gas chromatography–mass spectrometry (ID GC-MS) target values were assigned to all the materials. Intralaboratory within- and between-run imprecision results were very similar for all the materials tested (CV ≤2.20% and ≤4.70%, respectively). The overall imprecision obtained was high (CV 6.5–20.0%) because of increased interlaboratory–intermethod variability. A significant positive bias (+9.2–+43.7%) was found for all the materials at lower creatinine concentration. By using two human sera at different concentrations, we could calculate the constant and the proportional calibration bias displayed by each peer group. The majority of the lyophilized materials showed a behavior divergent from the frozen pools, indicating matrix-related problems. We propose a new algorithm for calculating matrix bias correction factor instrument–reagent specific for each material.read more
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Recommendations for Improving Serum Creatinine Measurement: A Report from the Laboratory Working Group of the National Kidney Disease Education Program
Gary L. Myers,W. Greg Miller,Josef Coresh,James K. Fleming,Neil Greenberg,Tom Greene,Thomas H. Hostetter,Andrew S. Levey,Mauro Panteghini,Michael J. Welch,John H. Eckfeldt +10 more
TL;DR: The NKDEP Laboratory Working Group has developed a plan that enables standardization and improved accuracy (trueness) of serum creatinine measurements in clinical laboratories worldwide that includes the use of the estimating equation for GFR based on serum Creatinine concentration that was developed from the Modification of Diet in Renal Disease (MDRD) study.
Journal ArticleDOI
Serum Creatinine: Not So Simple!
TL;DR: This review mainly focuses on the analytical limitations of serum creatinine, insisting on important concept such as reference intervals, standardization, analytical interferences, analytical Interference, analytical coefficient of variation (CV), biological CV and critical difference.
Journal ArticleDOI
Does the ID-MS traceable MDRD equation work and is it suitable for use with compensated Jaffé and enzymatic creatinine assays?
TL;DR: This study evaluates the use of isotope dilution mass spectrometry, the compensated Jaffe and enzymatic creatinine methods compared with the Beckman CX3 Jaffe assay used to derive the MDRD equation and investigates their impact on GFR estimation using both the original and ID-MS-traceable MDRd equations.
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A multicentric evaluation of IDMS-traceable creatinine enzymatic assays
Laurence Piéroni,Pierre Delanaye,Anne Boutten,Anne-Sophie Bargnoux,Eric Rozet,Vincent Delatour,Marie-Christine Carlier,Anne-Marie Hanser,Etienne Cavalier,Marc Froissart,Jean-Paul Cristol +10 more
TL;DR: This study demonstrates substantial improvements in the calibration, traceability and precision of the enzymatic methods, reaching the NKDEP recommendations.
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Specimen materials, target values and commutability for external quality assessment (proficiency testing) schemes.
TL;DR: In this article, a matrix-modified processed materials are used in most programs, because they can be produced in large quantities, can have multiple abnormal analytes in the same vial and have excellent stability.
References
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Journal ArticleDOI
Analytical Reviews in Clinical Biochemistry: The Estimation of Creatinine:
TL;DR: Creatinine is formed by a spontaneous and irreversible conversion from creatine and creatine phosphate, and about 2% of whole body creatine is so transformed every 24 h, Consequently, creatinine formation also has a direct relationship to total muscle mass and roughly to the body weight.
Proposed quality specifications for the imprecision and inaccuracy of analytical systems for clinical chemistry.
TL;DR: Quality specifications for analytical systems for clinical chemistry are proposed and total imprecision should be less than one-half of the average within-subject biological variation or the state of the art achieved by the best 0.20 fractile of laboratories.
Journal ArticleDOI
Candidate reference methods for determining target values for cholesterol, creatinine, uric acid, and glucose in external quality assessment and internal accuracy control. II. Method transfer.
TL;DR: The presented candidate Reference methods, based on isotope dilution-gas chromatography--mass spectrometry methods that have been developed at INSTAND, have been successfully used to set target values in the German EQA scheme and the internal accuracy control of routine laboratories.
Journal Article
Accuracy verification and identification of matrix effects. The College of American Pathologists' Protocol.
John H. Eckfeldt,Copeland Kr +1 more
TL;DR: The purpose of this investigation was to determine the feasibility, usefulness, and potential problems associated with this CAP Matrix Effect Analytical Protocol, in which fresh patient specimens and CAP proficiency specimens are analyzed simultaneously by a field method and a definitive, reference, or other comparative method.
Journal ArticleDOI
Quality control in clinical chemistry: characterization of reference materials.
TL;DR: Several techniques are described that characterize specimens used in the quality-control or calibration of laboratory procedures that apply to two clinical analytes-theophylline and alkaline phosphatase.