A tubular test device for testing occult blood in fecal matter using hydrogen peroxide in an ampoule and 3,3',5,5'-tetramethylbenzidine as the chromogen dissolved in chloroform to impregnate a cellulosic pledget which, when dried, is substantially colorless and is introduced adjacent a sampling swab...http://www.google.fr/patents/US4562043?utm_source=gb-gplus-shareBrevet US4562043 - Self-contained swab cartridge apparatus for detecting occult blood
Self-contained swab cartridge apparatus for detecting occult blood
