Semin Thromb Hemost 2008; 34(4): 340-346
DOI: 10.1055/s-0028-1085476
© Thieme Medical Publishers

Technical Aspects in Laboratory Testing for Antiphospholipid Antibodies: Is Standardization an Impossible Dream?

Guido Reber1 , Françoise Boehlen1 , Philippe de Moerloose1
  • 1Haemostasis Unit, Division of Angiology and Haemostasis, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
Further Information

Publication History

Publication Date:
23 September 2008 (online)

ABSTRACT

Anticardiolipin (aCL) and anti-β2 glycoprotein I (anti-β2GPI) assays are widely performed because they are part of the laboratory criteria for the antiphospholipid syndrome (APS). Despite several standardization workshops and the availability of a worldwide accepted calibrator material for aCL, a high variability in numerical assay results and in sample classification is still observed in comparative studies and external quality control surveys. For anti-β2GPI assays, comparison of numerical values is impeded by the absence of a common calibrator material, and external quality surveys similarly show a large overlap in sample classification. Numerous variables impact assay results, among them the source and integrity of β2GPI, the secondary calibration process, and the assessment and derivation of cutoff values. For both assays, the vast majority of laboratories use commercial kits whose number has risen considerably in the past years. However, many problems persist, and there is a need to improve the comparability in assay results. The use of monoclonal antibodies as reference calibrators has to be especially considered, with their suitability evaluated by future collaborative studies and external quality controls surveys. Manufacturers should provide more precise information on results obtained when testing control groups for establishing reference ranges and cutoff values. From the customers' perspective, it is important that each laboratory, even if using commercial kits, assesses its local cutoff value whenever possible. In the field of autoimmunity, assay standardization is a difficult but nevertheless important task. Much more effort is needed to reduce the high interlaboratory variability in assay results even if absolute standardization cannot be feasibly achieved.

REFERENCES

Dr. Guido Reber

Haemostasis Unit, Geneva University Hospital, 25 rue Micheli-du-Crest

1211 Geneva 14, Switzerland

Email: guido.reber@hcuge.ch

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