[The Program of External Quality Evaluation in Clinical Chemistry. An overview and evaluation after 11 years of functioning].

After an eleven-year period, the goals and way of functioning are remembered the External Quality Assessment Scheme in Clinical Chemistry, under the responsibility of the National Institute of Health. The authors try to evaluate the quality of results obtained at the time by the 160 participant laboratories, belonging to the public and private sectors as well as to the Portuguese reference laboratories which have to assign the expected values on the control sera to be analysed. As regards the 22 biochemical blood parameters, we came to the conclusion that there is a high performance level in what concerns the reference laboratories and a quality level of participant laboratories in accordance with their considered peer foreign laboratories.