Benzidine test

benzidine testBenzidine test - detect blood in the urine, feces, the contents of the stomach by benzidine reagent (solution of benzidine in acetic acid + hydrogen peroxide). Urine and gastric juice should be filtered through a paper filter, and then to put on it reagent. In case of presence of blood appears blue or green staining (Fig. 1). Cal put a thin layer on a glass slide and add a few drops of benzidine reagent. At presence in Calais blood appears appropriate staining (Fig. 2 and 3).

Benzidine test - reaction used to detect blood in the stool, urine, gastric juice, vomit and based on the oxidation of benzidine (parliamentarily) hydrogen peroxide in the peroxidase-catalyzed actions blood pigment. Often use a modification of benzidine samples proposed by yens Gregersen collection (M Gregersen): mixed 0,025 g main benzidine and 0.1 g of peroxide of barium add (immediately before the examination) 5 ml of 50% solution of acetic acid and shake to dissolve benzidine. Peroxide of barium can be replaced by hydrogen peroxide; in this case prepare a saturated solution of benzidine in acetic acid and mix it with an equal amount of 3% solution of hydrogen peroxide.
Subject to investigation stool smear a thin layer on a glass slide and put on him a few drops of reagent. Liquid materials (urine, stomach contents, etc.) is placed in the volume of 1 ml in a test tube and add 5-6 drops of reagent; sometimes samples of the produce on filter paper, through which filtered 50-100 ml of the investigated liquid. In the presence of blood turns a bright blue or green colour. Sensitivity benzidine samples 1:100 000. In the study of feces positive results can be obtained through the blood pigments contained in food. Therefore, prior to bpts need for three days to avoid meat and meat Navara from food ration investigated. Bpts usually produce for suspicion of hidden bleeding.