The effects of common matrices for assay standards on performance of ültra sensitive" immunometric assays for TSH. Report of a joint WHO/IFCC collaborative study
Ann.Biol.Clin.(Paris), 49 (10):
522-527 (1991)Abstract
This report describes the results of a collaborative study organized by a joint working group of IFCC and WHO and involving nine manufacturers of TSH immunometric assay kits. The study was designed to determine whether a calibrator with a common matrix gives better between-laboratory agreement for calibration of serum samples than the various kit calibrators, and to assess various materials for their suitability for use as common matrices. Kit calibrators or calibrators consisting of the IRP for TSH made up in two common matrices, 1) serum from patients with untreated thyrotoxicosis or 2) serum taken from subjects treated with suppressive doses of triiodothyronine, gave similar results for the between-laboratory variation of estimates of TSH concentration for a range of serum samples. Dose-response curves for the two calibrators in 'common' matrices were similar to one another and to those fort the kit calibrator. However, the occurrence of non-specific serum effects is shown by the co