title: The impact of sequential quality assessment exercises on laboratory performance: the multicentre ECAT Angina Pectoris Study. Report from the European Concerted Action on Thrombosis and Disabilities (ECAT).
abstract: As an adjunct to a European multicentre prospective study, five quality assessment (QA) exercises, spanning a period of 2.5 years, were undertaken. In these, fifteen laboratories from eight countries each performed ten haemostatic factor assays. The design of the QA exercises allowed the between-duplicate, between-day and between-laboratory coefficients of variation (CVs) to be calculated. The between-duplicate CV decreased by a factor of one quarter, and the between-day CV by a factor of one third, over the five exercises. The activated partial thromboplastin time (APTT) assay consistently showed the lowest CVs, while there was notable improvement in the between-day CVs for von Willebrand factor related antigen (vWF R:Ag) and factor VIII clotting activity (VIII:C). However, the between-laboratory CV, assessing extent of agreement between the different laboratories, did not apparently improve over the five exercises. Thus, while QA exercises may be very useful in improving the performance of haemostatic assays according to criteria which an individual laboratory can assess, improving agreement on haemostatic assay results between laboratories may be more difficult to achieve.
authors.affiliation: Medical Statistics Unit, London School of Hygiene and Tropical Medicine, United Kingdom.
authors.forename: S G
authors.initials: SG
authors.lastname: Thompson
authors.forename: G
authors.initials: G
authors.lastname: Calori
authors.forename: J M
authors.initials: JM
authors.lastname: Thomson
authors.forename: F
authors.initials: F
authors.lastname: Haverkate
authors.forename: F
authors.initials: F
authors.lastname: Duckert
mesh_terms: D000787:Angina Pectoris / Q000097:blood*; D001780:Blood Coagulation Tests / Q000592:standards*; D005060:Europe; D006801:Humans; D007753:Laboratories / Q000592:standards*; D011446:Prospective Studies; D011785:Quality Assurance, Health Care; D015203:Reproducibility of Results