A multicenter study to assess the reproducibility of antiphospholipid antibody results produced by an automated system

K M Devreese; A Poncet; E Lindhoff-Last; J Musial; P de Moerloose; P Fontana

doi:10.1111/jth.13560

A multicenter study to assess the reproducibility of antiphospholipid antibody results produced by an automated system

J Thromb Haemost. 2017 Jan;15(1):91-95. doi: 10.1111/jth.13560. Epub 2016 Dec 18.

Authors

K M Devreese¹, A Poncet², E Lindhoff-Last³, J Musial⁴, P de Moerloose⁵, P Fontana⁵

Affiliations

¹ Coagulation Laboratory, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, Ghent, Belgium.
² CRC and Division of Clinical-Epidemiology, Department of Health and Community Medicine, University of Geneva and University Hospitals of Geneva, Geneva, Switzerland.
³ Cardiology Angiology Center Bethanien (CCB) Vascular Center-Coagulation Center, Frankfurt, Germany.
⁴ Department of Medicine, Jagiellonian University Medical College, Krakow, Poland.
⁵ Division of Angiology and Haemostasis, Faculty of Medicine, University Hospitals of Geneva and Geneva Platelet Group, Geneva, Switzerland.

PMID: 27813343
DOI: 10.1111/jth.13560

Abstract

Essentials Inter-lab variation studies for antiphospholipid antibodies (aPL) with the same assay are lacking. We carried out an assessment of repeatability and reproducibility of an automated aPL assay. High intra-center repeatability for anticardiolipin and aβ₂ GPI makes duplicate testing unnecessary. Inter-lab reproducibility was high except for aβ2GPI IgG.

Summary: Background Inter-assay variability is a well-known problem in antiphospholipid antibody testing, because of the lack of standardization. Inter-laboratory reproducibility for the same assay is similarly important. Objectives Testing repeatability and reproducibility of HemosIL^® AcuStar for anticardiolipin (aCL) and antiβ2-glycoprotein I antibodies (aβ2GPI) IgG and IgM. Patients/Methods In this observational study, out of 420 samples from the thrombophilia centers of Ghent and Geneva, 100 samples were randomly selected and successively analyzed in three centers: Ghent (C1, in duplicate for repeatability evaluation), Geneva (C2) and Frankfurt (C3). Results Results from 99 samples were available, including 25 from patients with antiphospholipid syndrome (APS) and 74 from non-APS patients. The intra-center repeatability expressed as intra-class correlation coefficient (ICC) was higher than 0.99 for each parameter. Differences between two measurements rarely exceeded 1 U mL^-1 for values below 100 U mL^-1 , except for aβ2GPI IgG, where differences varied from -4 to 4 U mL^-1 . The inter-center ICCs were higher than 0.99, except for aCL IgM (ICC = 0.961). These ICCs remained high even when considering values below 100 U mL^-1 (0.943, 0.964 and 0.977 for aCL IgG, aCL gM and aβ2GPI IgM, respectively), except for aβ2GPI IgG (ICC = 0.652). Qualitative comparison showed less than 5% discordant classification between centers, with somewhat more discordant results for aβ2GPI IgG. Conclusions In terms of discriminating properties, the HemosIL^® AcuStar has excellent intra-center repeatability and a good inter-center reproducibility for aCL IgG, aCL IgM and aβ2GPI IgM. Some concern may arise for aβ2GPI IgG.

Keywords: anticardiolipin; antiphospholipid antibodies; reproducibility; β2glycoprotein I.

Publication types

Multicenter Study
Observational Study

MeSH terms

Antibodies, Antiphospholipid / blood*
Antiphospholipid Syndrome / immunology
Automation
Female
Humans
Immunoglobulin G / blood
Immunoglobulin M / blood
Luminescent Measurements / standards*
Pregnancy
Reproducibility of Results
Thrombophilia
beta 2-Glycoprotein I / immunology

Substances

Antibodies, Antiphospholipid
Immunoglobulin G
Immunoglobulin M
beta 2-Glycoprotein I