[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%. Comparison with the urease/GLDH, Berthelot and diacetylmonoxim tests on sera from routine samples indicated good agreement of results even for pathological samples. Using whole blood there was also good agreement with results with plasma of the same samples. The Reflotest-Urea method is simple because different dose ranges can be used and the reaction time of ten minutes is not crucial. In-vitro studies using 37 of the most commonly used drugs in different areas of medicine failed to reveal any interference with the test.