J. Endocrinol. Invest. 17: 355-365,1994 CONSENSUS STATEMENT Italian serum exchange workshop for the standardization of organ specific autoantibodies U. Oi Mario*, C. Betterle**, F. Oondero***, G.F. Fenzi****, S. Mariotti***** and F. Trimarchi******, on behalf of the ImmunoEndocrinology Study Group of the Italian Society of Endocrinology and participating laboratories 1 *Dipartimento di Medicina Clinica e Sperimentale, University of RC-Catanzaro, **Istituto di Semeiotica Medica, Allergologia e Immunologia Clinica, University of Padova, ***Dipartimento di Medicina Interna, Unita di Semiologia e Immunologia della Riproduzione, University of Roma - La Sapienza, ****Istituto di Endocrinologia, University of Napoli, *****Istituto di Endocrinologia, University of Pisa, ******Istituto di Endocrinologia, University of Messina, Italy 1. WORKSHOP PROGRAM 1 .1. Background Organ specific autoantibodies are diagnostic sup- portive in a number of different pathologies. Most of techniques to measure them are semiquantitative or give a positive/negative value and a number of factors may affect the results. Several multicenter serum exchange workshops have been organized to enhance assay sensitivity, precision and repro- 1 Participating laboratories: M. Bagnasco, S. Buscaglia, G.P. Pesce (Genova) A. Bellastella, A. De Bellis, AA Sinisi (Napoli) C. Betterle, F. Presotto, R. Zanchetta (Padova) E. Bosi, N. Dozio, F. Fusi (Milano) R. Calafiore, M.L. Picchio, G. Basta (Perugia) Q. Carta, E. Fruttero, S. Pinach (Torino) R. De Pirro r, R. Galassi (Ancona) E. Di Cesare, M. Previti, D. Cucinotta (Messina) U. Di Mario, E. Anastasi, C Tiberti (Roma) F. Dondero, A. Lenzi, L. Gandini (Roma) F. Franchi, M. Gasperi, D. Barletta (Pisa) F. Francavilla, R. Romano, R. Santucci (L'Aquila) A. Galluzzo, C. Giordano, G. Stassi (Palermo) G. Ghirlanda, E. Ponte, F. Scuderi (Roma) F. Lore, D.F. D'Ubaldo, G. Di Cairano (Siena) M. Salvi, R. Minelli, D. Dazzi (Parma) S. Mariotti, P Caturegli, A. Pinch era (Pisa) G. Iacono, A. Bizzarro, C. Carella (Napoli) F. Trimarchi, S. Benvenga, S. Battiato (Messina) G.L. Turco, C. Brossa (Torino) R. Vigneri, M. Buscema, F. Purrello (Catania) tdeceased Key-words: thyroid-autoantibodies, islet-cell autoantibodies, adrenal- au- toantibodies, sperm-autoantibodies. Correspondence: Prof. U. Di Mario, Policlinico Mater Domini, 88100 Catanzaro, Italy. This report summarizes the work of a serum exchange workshop for the standardization of organ specific autoantibodies organized by the Italian Society of Endocrinology. 355 ducibility while yet maintaining specificity for dis- ease. 1.2. Study aims (1) To evaluate the inter-laboratory and intra-assay variations, (2) to highlight the main factors respon- sible for the analytical variability, (3) to optimize and standardize methodologies and (4) to select poten- tial reference laboratories for further studies or qual- ity control for others willing to compare their assays. 1 .3. Study design The workshop focused on 4 families of autoanti- bodies: thyroid-, islet cell-, adrenal- and sperm- au- toantibodies. Twenty different laboratories, indicat- ed alphabetically, participated in the workshop. In addition to those in 1.2, other specific aims were se- lected for each autoantibody workshop. 1.4. Evaluation of results Results were evaluated on the analysis of sensitiv- ity, specificity and validity. Sensitivity indicates the capacity of the laboratory to avoid false negatives i.e., the level of concordance with the positive ref- erence sera. Specificity indicates the capacity of the laboratory to avoid false positives, i.e., the lev- el of concordance with the reference seraValidity indicates the capacity of the laboratory to repro- duce the positive results as positive and the nega- tive results as negative. 2. THYROID AUTOANTIBODIES The purpose of this section was to assess some of the currently employed techniques to detect an- tithyroglobulin (anti-Tg) and anti-thyroid microso-