IFCC reference procedures for measurement of the catalytic concentrations of enzymes: corrigendum, notes and useful advice

Abstract

The primary reference measurement procedures (PRMPs) for the international standardization of catalytic concentration measurements of alpha-amylase, alanine aminotransferase, aspartate aminotransferase (AST), creatine kinase (CK), gamma-glutamyltransferase and lactate dehydrogenase have been performed in reference laboratories for several years. The IFCC Committee on Reference Systems for Enzymes and two reference laboratories, with official accreditation for the PRMPs, have collected useful information on some of the steps of the reference procedures that require special attention. This document comprises errata corrige for minor mistakes in published PRMPs for AST and CK. Several notes on the PRMPs are emphasized. This includes details that are very important for improved standardization, and general suggestions for reducing measurement uncertainty.

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

“…Although in the present study imidazole and creatine phosphate reagents' influences have been quantify only, an exhausted study of all employed chemical reagents should be carried out. Therefore, a procedure which allows identifying such a bias of at least 1.5% with a statistical significance (p < 0.05) is recommended [22].…”

“…In some cases, uncertainty contribution of this component may be quite important. The stability of CK in lyophilized samples may be dependent on temperature, the sensitivity of the enzyme against exposure to light can be very strong and the temperature of water for the reconstitution of certain lyophilized materials has a strong and irreversible influence on the catalytic activity concentration of CK [22]. Therefore, these uncertainty sources should not be underestimated.…”

Preliminary study of the relationship between promoter methylation of the ANGPTL2 gene and coronary heart disease

“…The plasma Lp(a) concentrations were determined by a sandwich enzyme‐linked immunosorbent assay method [Macra‐Lp(a); SDI, Newark, DE, USA]. The concentrations of ALT, AST, ALP, and GGT in plasma were measured by the IFCC reference measurement systems . The ALB level was worked through the bromocresol green method .…”

“…The concentrations of ALT, AST, ALP, and GGT in plasma were measured by the IFCC reference measurement systems. [21][22][23] The ALB level was worked through the bromocresol green method. 24 All the mentioned procedures were followed the standard procedures recommended by the manufacturers.…”

Evaluation of Quetiapine Fumarate and its Solid Lipid Nanoparticles as antipsychotic drug in rat model of schizophrenia

“…Assessment of liver function: The activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and creatine kinase (CK) were measured by commercial kits according to the method of IFCC (2010) (Schumann et al, 2010). Alkaline phosphatase (ALP) was measured by a commercial kit according to the method of Tietz (1994) (Tietz, 1994).…”