title: Impact of quality control matrix effect: application to the calculation of uncertainty of measurement in one-stage clotting factor VIII assay.
abstract: In Europe, the ISO 15 189 standard requires uncertainty of measurement to be calculated for all measurands. We calculated the analytical imprecision and bias of our factor VIII coagulometric assay method between 5 and 80 U/dl, using plasmas expected to be at 5, 30 and 80 U/dl of factor VIII. We implemented Meijer et al.'s [Clin Chem 2002; 48:1011-1015] long-term coefficient of variance, bias and also uncertainty of measurement calculations. Assessments used reference plasma diluted in severe haemophilic plasma, in immunodepleted factor VIII-deficient plasma and in bovine serum albumin. With plasmas diluted in severe haemophilic and immunodepleted factor VIII-deficient plasma, calculated uncertainty of measurement was 10% compared with 15% (i.e., 50% greater) for plasma diluted in albumin buffer or as calculated from European Concerted Action on Thrombosis consensus values. It is thus important to approximate the patient sample matrix to obtain as precise an estimation as possible of assay method uncertainty of measurement.
authors.affiliation: Edouard Herriot Hospital, Lyon, France. frederic.sobas@chu-lyon.fr <frederic.sobas@chu-lyon.fr>
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sobas
authors.forename: Norbert
authors.initials: N
authors.lastname: Benattar
authors.forename: Audrey
authors.initials: A
authors.lastname: Bellisario
authors.forename: Sylvie
authors.initials: S
authors.lastname: Marin
authors.forename: Christophe
authors.initials: C
authors.lastname: Nougier
authors.forename: Anne
authors.initials: A
authors.lastname: Lienhart
authors.forename: Claude
authors.initials: C
authors.lastname: Négrier
mesh_terms: D000818:Animals; D001681:Biological Assay; D001780:Blood Coagulation Tests; D042783:Endothelial Cells / Q000166:cytology; D005169:Factor VIII / Q000378:metabolism*; D006467:Hemophilia A / Q000097:blood / Q000235:genetics; D051379:Mice; D011786:Quality Control; D035501:Uncertainty
chemical_list: D005169:Factor VIII