title: Harmonisation of seven common enzyme results through EQA.
abstract: BACKGROUND
  Equivalent results between different laboratories enable optimal patient care and can be achieved with harmonisation. We report on EQA-initiated national harmonisation of seven enzymes using commutable samples.
  
  
  METHODS
  EQA samples were prepared from human serum spiked with human recombinant enzymes. Target values were assigned with the IFCC Reference Measurement Procedures. The same samples were included at four occasions in the EQA programmes of 2012 and 2013. Laboratories were encouraged to report IFCC traceable results. A parallel study was done to confirm commutability of the samples.
  
  
  RESULTS
  Of the 223 participating laboratories, 95% reported IFCC traceable results, ranging from 98% (ASAT) to 87% (amylase). Users of Roche and Siemens (97%) more frequently reported in IFCC traceable results than users of Abbott (91%), Beckman (90%), and Olympus (87%). The success of harmonisation, expressed as the recovery of assigned values and the inter-laboratory CV was: ALAT (recovery 100%; inter-lab CV 4%), ASAT (102%; 4%), LD (98%; 3%), CK (101%; 5%), GGT (98%; 4%), AP (96%; 6%), amylase (99%; 4%). There were no significant differences between the manufacturers. Commutability was demonstrated in the parallel study. Equal results in the same sample in the 2012 and 2013 EQA programmes demonstrated stability of the samples.
  
  
  CONCLUSIONS
  The EQA-initiated national harmonisation of seven enzymes, using stable, commutable human serum samples, spiked with human recombinant enzymes, and targeted with the IFCC Reference Measurement Procedures, was successful in terms of implementation of IFCC traceable results (95%), recovery of the target (99%), and inter-laboratory CV (4%).
authors.forename: Cas
authors.initials: C
authors.lastname: Weykamp
authors.forename: Paul
authors.initials: P
authors.lastname: Franck
authors.forename: Jacqueline Klein
authors.initials: JK
authors.lastname: Gunnewiek
authors.forename: Robert
authors.initials: R
authors.lastname: de Jonge
authors.forename: Aldy
authors.initials: A
authors.lastname: Kuypers
authors.forename: Douwe
authors.initials: D
authors.lastname: van Loon
authors.forename: Herman
authors.initials: H
authors.lastname: Steigstra
authors.forename: Christa
authors.initials: C
authors.lastname: Cobbaert
mesh_terms: D057075:Enzyme Assays / Q000295:instrumentation / Q000379:methods*; D004798:Enzymes / Q000097:blood*; D006801:Humans; D007753:Laboratories / Q000592:standards*; D011786:Quality Control; D011994:Recombinant Proteins / Q000097:blood; D012016:Reference Values
chemical_list: D004798:Enzymes; D011994:Recombinant Proteins