Re.: Correction to the IFCC primary reference method for the measurement of catalytic activity concentration of enzymes at 37C- part 2: reference procedure for the measurement of creatine kinase. Clin Chem Lab Med 2002;40:635-42

2004 ◽  
Vol 42 (3) ◽  
Author(s):  
William Graham Wood ◽  
Udo Kramer
Keyword(s):  
Creatine Kinase ◽  
Catalytic Activity ◽  
Activity Concentration ◽  
Reference Method ◽  
Reference Procedure ◽  
Primary Reference

IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C: International Federation of Clinical Chemistry and Laboratory Medicine (IFCC): Scientific Division, Committee on Reference Systems for Enzymes (C-RSE): Part 8. Reference procedure for the measurement of catalytic concentration of α-amylase: [α-Amylase: 1,4-α-D-glucan 4-glucanohydrolase (AMY), EC 3.2.1.1]

2006 ◽  
Vol 44 (9) ◽  
Author(s):  
G. Schumann ◽  
R. Aoki ◽  
C.A. Ferrero ◽  
G. Ehlers ◽  
G. Férard ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Catalytic Activity ◽  
Lactate Dehydrogenase ◽  
Alanine Aminotransferase ◽  
Clinical Chemistry ◽  
Reference Method ◽  
Reference Procedure ◽  
Activity Concentrations ◽  
Primary Reference

AbstractThis paper is the eighth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C and the certification of reference preparations. Other parts deal with: Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes; Part 2. Reference procedure for the measurement of catalytic concentration of creatine kinase; Part 3. Reference procedure for the measurement of catalytic concentration of lactate dehydrogenase; Part 4. Reference procedure for the measurement of catalytic concentration of alanine aminotransferase Part 5. Reference procedure for the measurement of catalytic concentration of aspartate aminotransferase Part 6. Reference procedure for the measurement of catalytic concentration of γ-glutamyltransferase; Part 7. Certification of four reference materials for the determination of enzymatic activity of γ-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase at 37°C. The procedure described here is deduced from the previously described 30°C IFCC reference method. Differences are tabulated and commented on.Clin Chem Lab Med 2006;44:1146–55.

Mass concentration and activity concentration of creatine kinase isoenzyme MB compared in serum after acute myocardial infarction

1990 ◽  
Vol 36 (1) ◽  
pp. 149-153 ◽  
Author(s):  
J R Delanghe ◽  
A M De Mol ◽  
M L De Buyzere ◽  
I K De Scheerder ◽  
R J Wieme
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Creatine Kinase ◽  
Catalytic Activity ◽  
Conformational Changes ◽  
Mass Concentration ◽  
Activity Concentration ◽  
Steady Increase ◽  
Reference Limit ◽  
Upper Reference Limit

Abstract We compared three current methods (immunoinhibition, "Isomune-CK" immunoprecipitation, and the Tandem-E CKMB II immunoenzymometric assay) for determination of creatine kinase (CK; EC 2.7.3.2) isoenzyme MB in serum. Although results inter-correlated well, the immunoinhibition assay gave higher activity values. Atypical CK forms did not interfere with the immunoprecipitation and immunoenzymometric methods. In acute myocardial infarction the catalytic properties of CK decreased with the enzyme's age, as reflected by a steady increase in activation energy of the catalyzed reaction. In septicemia patients with very low CK and CK-MB catalytic activity, mean CK-MB mass concentration exceeded the upper reference limit, suggesting an increased rate of loss of activity concentration in these patients' sera. Because of the assay's lesser susceptibility to conformational changes at the active site of the enzyme, we suggest that measurement of CK-MB mass concentration is better suited for infarct sizing than measurement of catalytic activity.

An approach to establish the uncertainty budget of catalytic activity concentration measurements in a reference laboratory

2015 ◽  
Vol 53 (5) ◽  
Author(s):  
Laura Rami ◽  
Francesca Canalias
Keyword(s):  
Catalytic Activity ◽  
Measurement Uncertainty ◽  
Activity Concentration ◽  
Uncertainty Budget ◽  
Reference Laboratory ◽  
Expanded Uncertainty ◽  
Iso 17025 ◽  
Reference Measurement ◽  
Uncertainty Sources ◽  
Primary Reference

AbstractReference laboratories providing reference services recognized by the Joint Committee for Traceability in Laboratory Medicine (JCTLM) must be accredited as calibration laboratories according to ISO 17025 and ISO 15195. These standards require laboratories to establish an uncertainty budget, in which the uncertainty contributions of the relevant uncertainty components are specified. We present a model to estimate the measurement uncertainty of creatine kinase catalytic activity concentration results obtained by IFCC primary reference measurement procedure.The measurement uncertainty has been estimated by following the next steps: 1) specification of the measurand; 2) identification of the most relevant uncertainty sources; 3) estimation of standard uncertainties by either type A or type B evaluation; 4) estimation of combined uncertainty while taking into account sensitivity coefficients, as well as existence of correlated uncertainty sources; and 5) estimation of expanded uncertainty with a defined coverage probability.The estimated expanded uncertainty was 2.2% (The present model is an approach to establish the uncertainty budget of primary reference procedures for the measurement of the catalytic activity concentration of enzymes, and aims at being an example to be followed by other reference laboratories, as well as by laboratories that carry out primary reference measurement procedures.

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