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Background: Using a questionnaire, the EC4 (European Communities Confederation of Clinical Chemistry and Laboratory Medicine) has collated an inventory of the accreditation procedures for medical laboratories in the EU., Results and Discussion: Accreditation of medical laboratories in the countries of the EU is mostly carried out in cooperation with national accreditation bodies. These national accreditation bodies work together in a regional cooperation, the European Cooperation for Accreditation (EA). Professionals are trained to become assessors and play a prominent role in the accreditation process. The extent of the training is diverse, but assessors are kept informed and up-to-date by annual meetings. The frequency of assessments and surveillance visits differs from country to country and ranges from 1 to 4 years. More harmonisation is needed in this respect, based on a frequency that can be pragmatically handled by laboratory professionals. In the majority of EA bodies, accreditation is carried out on a test-by-test basis. Many professionals would prefer accreditation of the entire service provided within the actual field of testing (i.e., haematology, immunology, etc.), with accreditation granted if the majority of tests offered within a service field fulfil the requirements of the ISO 15189 standard. The scope of accreditation is a major point of discussions between the EC4 Working Group on Accreditation and representatives of accreditation bodies in the EA Medical Laboratory Committee.

The responses of serum concentrations of TSH, thyroxine (T4), triiodothyronine (T3) and of reverse triiodothyronine (rT3) to i. v. administration of 0.4 mg THR were examined prior to (and after) i. m. administration of ACTH (2 mg Synacthen Depot) in 7 euthyroid women using estrogen-containing oral contraceptives and in 8 controls, with the following results: (1) an increase in endogenous glucocorticoid secretion is associated with a depression of the TSH response to TRH; (2) TSH formed in decreased amounts is still capable of stimulating thyroid secretion; (3) the increased serum corticoid levels fail to affect the secretory response of the thyroid to TSH; (4) control of the pituitary-thyroid axis remains normal in the presence of increased serum thyroxine-binding globulin (TBG) levels. In a further series the serum levels of TBG, T4, T3, rT3 and cortisol under the effect of ACTH-induced endogenous glucocorticoid hypersecretion were studied in 6 normal untreated controls, in 6 normal women using oral contraceptives and in 10 untreated hyperthyroid patients. During four days subsequent to treatment the serum TBG levels decreased, maximum decrease being found in the users of oral contraceptives, minimum decrease in the controls. Serum T4 was found to decrease during 2 to 4 days, serum T3 parallel with an increase in serum rT3, for 1 to 2 days, subsequent for ACTH loading. In the euthyroid cases also the serum TSH levels showed a transitory decline. It is concluded that in case of endogenous hyperproduction of glucocorticoids (1) T4 leads to T3 monodeiodination decreases and T4 leads to rT3 conversion increases parallel with the changes in the serum cortisol levels; (2) TBG synthesis is inhibited by endogenous glucocorticoids; (3) the changes in serum TBG levels are accompanied by a decrease in the serum T4 concentrations.