Harmonisation of factor VIII:C assay results: study within the framework of the Dutch project ‘Calibration 2000’

• Published in: British journal of haematology 2006-01, Vol.132 (1), p.75-79
• Main Authors: Van Den Besselaar, Anton M. H. P., Haas, Fred J. L. M., Kuypers, Aldy W. H. M.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blood Coagulation Tests - standards; Calibration; commutability; external quality assessment; Factor VIII - analysis; factor VIII:C assay; harmonisation; Hematologic and hematopoietic diseases; Hematology; Hemophilia A - diagnosis; Humans; Laboratories - standards; Male; Medical sciences; Netherlands; Quality Assurance, Health Care - methods; Reproducibility of Results
• ISSN: 0007-1048; 1365-2141
• DOI: 10.1111/j.1365-2141.2005.05829.x

Summary In a Dutch project for harmonisation of factor VIII coagulant activity (FVIII:C) assays, the commutability of potential calibrators for FVIII:C was assessed by means of a ‘twin‐study design’, which is in essence a multi‐centre, split‐patient sample, between‐field‐methods protocol. Commutability was defined as the degree to which a material yielded the same numerical relationships between results of measurements by a given set of measurement procedures as those between the expectations of the relationships for the same procedures applied to those types of material for which the procedures were intended. The study consisted of the simultaneous analysis of fresh frozen patient plasmas and three potential calibrators for FVIII:C by 16 Dutch laboratories forming eight couples. The state‐of‐the‐art intra‐laboratory standard deviation was used to assess the commutability of the potential calibrators. One potential calibrator was used to harmonise FVIII:C assay results in a Dutch field study. The inter‐laboratory coefficient of variation of two test samples could be reduced significantly, but no significant effect was observed with three other test samples. We recommend that at least three different sample dilutions be used in each FVIII:C assay, in agreement with previous recommendations.