RESUMO
Several clinical laboratories in different regions of Spain have shared the search for reference individuals and the production of reference values for quantities concerning thyrotropin, non-protein bound thyroxine, triiodothyronine, cobalamines and folates, using an Elecsys 2010 analyser. All the logistic work has been done in co-operation with the supplier of the analyser (Roche Diagnostics España, S.L., Barcelona). The reference limits produced in the virtual laboratory are in fact derived from the blend of reference values obtained by each laboratory. The multicentric reference limits were estimated according to the recommendations of the International Federation of Clinical Chemistry. The work done represents a model of co-operation between the in vitro diagnostic industry and clinical laboratories for the production of reference values.