title: Standardization of autoantibody testing: a paradigm for serology in rheumatic diseases.
abstract: Autoantibody measurement is an excellent tool to confirm the diagnosis of rheumatic autoimmune diseases. Hence, reliability and harmonization of autoantibody testing are essential, but these issues are still a matter of debate. Intrinsic variability in analytes and reagents as well as heterogeneity of the techniques are the main reasons for discrepancies in inter-laboratory variations and reporting of test results. This lack of reliability might be responsible for wrong or missed diagnoses, as well as additional costs due to assay repetition, unnecessary use of confirmatory tests and/or consequent diagnostic investigations. To overcome such issues, the standardization of autoantibody testing requires efforts on all aspects of the assays, including the definition of the analyte, the pre-analytical stages, the calibration method and the reporting of results. As part of such efforts, the availability of suitable reference materials for calibration and quality control would enable the development of a reliable reference system. Strong-positive sera from patients have been used as reference materials in most of the autoantibody assays for rheumatic diseases; however, antigen-affinity-purified immunoglobulin fractions or in some cases reliable monoclonal antibody preparations offer more adequate tools for standardization. Systematic assessments of reference materials are currently underway, and preliminary results appear to be encouraging.
authors.affiliation: Department of Clinical Sciences and Community Health, Division of Rheumatology, Istituto G. Pini, University of Milan, Piazza C. Ferrari 1, 20122 Milan, Italy.
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Meroni
authors.affiliation: Department of Clinical Sciences and Community Health, Division of Rheumatology, Istituto G. Pini, University of Milan, Piazza C. Ferrari 1, 20122 Milan, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Biggioggero
authors.affiliation: Divisions of Rheumatology and Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555-0883, USA.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Pierangeli
authors.affiliation: Protein Reference Unit, St George's Hospital, Blackshaw Road, London SW17 0NH, UK.
authors.forename: Joanna
authors.initials: J
authors.lastname: Sheldon
authors.affiliation: European Commission Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, B-2440 Geel, Belgium.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Zegers
authors.affiliation: Istituto Auxologico Italiano, Experimental Laboratory of Immune-Rheumatology, Via G. Zucchi 18, 20095 Cusano Milanino, Milan, Italy.
authors.forename: Maria Orietta
authors.initials: MO
authors.lastname: Borghi
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D002138:Calibration / Q000592:standards; D006801:Humans; D007391:International Cooperation; D012015:Reference Standards; D015203:Reproducibility of Results; D012216:Rheumatic Diseases / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D012698:Serologic Tests / Q000592:standards*
chemical_list: D001323:Autoantibodies