Has the introduction of the European Parliament Directive 98/79/EC from 1998-10-27--concerning in-vitro diagnostic devices (IVD-directive) influenced performance of hormone immunoassay kits in terms of precision and accuracy? Results from selected external quality assessment (EQA) schemes between 1993 and 2008.

The aim of this report is to examine what--if any--effects the introduction of the European Directive 98/79/EC has had on the performance of in-vitro diagnostic devices (kits) used in determining hormones and related measurands in medical diagnostic laboratories. The observations covered the period from 1993-2008, results being taken from EQA surveys at three year intervals. The measurands chosen were: cortisol, progesterone, testosterone, 17beta oestradiol (E2), free triiodothyronine (fT3), total triiodothyronine (TT3), free thyroxine (fT4), total thyroxine (TT4), thyrotropin (TSH), luteotropin (LH), follitropin (FSH), prolactin (PRL), parathyrin (PTH), thyroglobulin (Tg), anti-thyroid microsomes (MAb), anti-thyroid peroxidase (Anti-TPO), anti-thyroglobulin (Anti-Tg) and anti-TSH-receptor (TRAb). The results showed the following trends and tendencies: a. The precision has improved over the observation period, mainly due to automation made possible by the use of non-radioisotopic labelling. b. The accuracy--in terms of comparison with reference method values--has not been influenced by the Directive 98/79/EC. c. Introduction of international standards and reference preparations does not itself result in better comparison of results between kits from different manufacturers. d. Harmonisation in methodology has led to improved comparison between different manufacturers--an example being the assay of thyroid-receptor antibodies, where components are often only available from one producer.