title: A Review of beta2 -glycoprotein-l antibody testing results from a peer-driven multilaboratory quality assurance program.
abstract: We evaluated the results of lgG beta2-glycoprotein-I (B2GPI) antibody assays in a multilaboratory setting by analyzing data from an external quality assurance program for the 2003 through 2005 cycles for 27 serum samples, including quantitative IgG-B2GPI values and qualitative interpretation and grading (ie, negative or positive; grade of positivity), according to method type and in conjunction with clinical data. We report high interlaboratory variation in numeric IgG-B2GPI results, comparable to that reported for IgG anticardiolipin antibody (aCL) testing, and some method-based variation. For example, interlaboratory coefficients of variation for IgG-B2GPI were more than 50% in 19 samples (70%). For qualitative reporting, there was generally better consensus than previously reported for semiquantitative IgG-aCL testing; although 100% consensus occurred for only 11 samples (41%), more than 90% of laboratories agreed for 19 samples (70%). In some cases, laboratory findings (negative or positive IgG-B2GPI) did not agree with clinical information. Despite the lack of formal standardization for IgG-B2GPI testing compared with IgG-aCL, there seems to be better cross-laboratory consensus. Improvement in standardization of these assays is still required to improve interlaboratory and intermethod concordance of results and interpretation between laboratories and the clinical usefulness of IgG-B2GPI testing.
authors.affiliation: Department of Haematology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, NSW, Australia.
authors.forename: Emmanuel J
authors.initials: EJ
authors.lastname: Favaloro
authors.forename: Richard C W
authors.initials: RC
authors.lastname: Wong
authors.forename: Susan
authors.initials: S
authors.lastname: Jovanovich
authors.forename: Peter
authors.initials: P
authors.lastname: Roberts-Thomson
mesh_terms: D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000097:blood; D001323:Autoantibodies / Q000097:blood*; D019411:Clinical Laboratory Techniques / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D053482:beta 2-Glycoprotein I / Q000276:immunology*
chemical_list: D017153:Antibodies, Anticardiolipin; D001323:Autoantibodies; D007074:Immunoglobulin G; D053482:beta 2-Glycoprotein I