[Determination of triiodothyronine in serum with a heterologous enzyme immunoassay: results of a group survey].

This paper summarises the results of the evaluation of a heterologous enzyme immunoassay in antibody coated tubes for the determination of triiodothyronine (T3) by a group of 11 laboratories. The assay procedure is analogous to an established heterologous thyroxine enzyme immunoassay. The evaluation demonstrated that 1.

[Determination of urea in blood and serum by the reflotest-urea method (author's transl)].

Tests in five laboratories on pooled sera in three concentration ranges demonstrated good reproducibility of urea concentration with the Reflotest-Urea, at a variation coefficient from 2.4% to 5.0%.