The first external quality control survey (EOCS) for antithyroglobulin- and antimicrosomal antibody determination

Fourteen laboratories participated in an external quality control survey (EQCS) for antithyroglobulin- and antimicrosomal-antibody determination. Seventeen frozen serum samples from individuals suffering from various thyroid diseases were dispatched by mail. Different test systems were used by the participants including the haemagglutinatin test, radioimmunoassay (RIA), enzyme immunoassay (ELISA) and immunofluorescence test. The different test results of each participant were sized and could be compared by giving place numbers to each test result. Inter-laboratory quality control was performed by evaluation of a rank correlation coefficient. There was close agreement between the haemagglutination test results of antimicrosomal antibody determination with different test kits, and these tests showed good precision. Antithyroglobulin antibody titers from the two haemagglutination test-kits used, however, were not directly comparable. When sized by place numbers, antithyroglobulin antibody results from haemagglutinatin test, RIA and ELISA were in close agreement. The least correspondence was shown by the immunofluorescence test, in the antithyroglobulin antibody determination.