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Semin Thromb Hemost 2005; 31(1): 73-84
DOI: 10.1055/s-2005-863808
Copyright © 2005 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA.

A Multilaboratory Peer Assessment Quality Assurance Program-Based Evaluation of Anticardiolipin Antibody, and beta2-Glycoprotein I Antibody Testing

Emmanuel J. Favaloro1 , 2 , Richard C. W. Wong4 , Roger Silvestrini3 , Robert McEvoy5 , Susan Jovanovich5 , Peter Roberts-Thomson5
  • 1Senior Scientist in Charge, Haemostasis Laboratories, Departments of Haematology and Immunopathology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Walls, Australia
  • 2Department of Haematology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Walls, Australia
  • 3Department Immunopathology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Walls, Australia
  • 4Division of Immunology, Queensland Health Pathology Services, Princess Alexandra & Royal Brisbane Hospitals, Brisbane, Australia
  • 5Royal College of Pathologists of Australasia Quality Assurance Program Pty Ltd, Flinders Medical Centre, Adelaide, Australia
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Publication History

Publication Date:
11 February 2005 (online)

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ABSTRACT

We evaluated the performance of anticardiolipin (aCL) and beta2-glycoprotein I (β2-GPI) antibody assays through a large external quality assurance program. Data from the 2002 cycle of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP) were analyzed for variation in reported numerical values and semiquantitative results or interpretations according to method type or group and in conjunction with available clinical data. High interlaboratory variation in numerical results and notable method-based variation, combined with a general lack of consensus in semiquantitative reporting, continues to be observed. Numerical results from cross-laboratory testing of 12 serum samples (for immunoglobulin G [IgG]-aCL, IgM-aCL, and IgG-β2-GPI) yielded interlaboratory coefficients of variation (CVs) that were higher than 50% in six of 12 (50%) specimens for IgG-aCL, and 12 of 12 (100%) specimens for IgM-aCL and IgG-β2-GPI. Semiquantitative reporting also varied considerably, with total (100%) consensus occurring in only four of 36 (11%) occasions. General consensus (where > 90% of participating laboratories agreed that a given serum sample gave a result of either negative or positive) was only obtained on 13 of 36 (36%) occasions. Variation in results between different method types or groups were also present, resulting in potential biasing of the RCPA QAP-defined target results by the large number of laboratories using the dominant aCL assays. Finally, laboratory findings frequently did not agree with the available clinical information. In conclusion, in a large proportion of specimens from the 2002 RCPA QAP cycle, laboratories could not agree on whether a serum sample tested was aCL-positive or aCL-negative, or β2-GPI-positive or β2-GPI-negative. Despite prior attempts to improve the standardization of testing and reporting practices, laboratory testing for aCL and anti-β2-GPI still demonstrates significant interlaboratory and intermethod variation, which needs to be taken into account for the clinical interpretation of test results, especially those from different laboratories.

KEYWORDS

Anticardiolipin antibody - antiphospholipid antibody - assays - laboratory assessment - quality assurance - antiphospholipid syndrome

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 Dr.
E. J FavaloroPh.D. 

Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR)

WSAHS, Westmead, New South Walls, 2145, Australia

Email: emmanuel@icpmr.wsahs.nsw.gov.au