Chemical examination of feces

Fecal blood discover methods, based on the action of hemoglobin pseudoperoxidase. Hemoglobin takes hydrogen from some organic compounds (benzyl- Dina, amidopirina, guaiac, ortotoluidina et al.) and transmits it to hydrogen peroxide, thus formed dye compound.

Benzidinovaya sample (Gregersena). To prepare the reagent Gregersen take the tip of a knife and the main benzidine dissolved in 5 ml 50 % acetic acid, was added an equal amount 3 % hydrogen peroxide solution or diluted 10 hydrogen peroxide solution was again concentrated (perhydrol).

Undiluted feces deposited a thick layer on the glass slide, placed in a petri dish, lying on a white background, was added a few drops of reagent and mixed thoroughly Gregersen. When a positive response in 1-2 minutes smear painted in green or blue-green color. Colouration, will come at a later date, ignored.

Instead of hydrogen peroxide can be used barium peroxide: 0,25 g of basic benzidine and 0,1 g barium peroxide dissolved in 5 ml 50 % acetic acid. The reagent is prepared immediately before use. With this method the sample is more sensitive.

Test with guaiac (Weber van Leena). Compared with benzidine this test is much less sensitive - it detects the presence of fecal less 5 % blood. Minor bleeding using this test can not diagnose. Test with amidopirinom more sensitive compared to guaiac.

Proximate method. As the reagents used ortotolidin (1 part by weight), barium peroxide (1 part by weight), tartaric acid (1 part by weight), calcium carbonate (20 parts by weight). The mixture of reagents was triturated in a mortar, and then tableted or consumed in the form of powder.

To conduct the study about 0,3 grams (pinch) placed on white filter paper and wetted with 2- 3 diluted with water drops feces. In the presence of blood through the powder 2 minute turns blue, and around it there is a bright blue aura.

Sensitivity tests: 3-5 Erythrocytes in the field of view (4000- 4500 erythrocytes 1 ml).

If any fecal occult blood necessary, to glassware and reagents were of chemically pure. During the three days before the study, patients prescribed a diet, excluding meat, fish, eggs, tomatoes, products, contain chlorophyll, and etc. Prohibits drugs, comprising iron, copper and other heavy metals.

Stercobilin. Some urobilinogen, formed in the intestines, excreted in the feces and called sterkobilinogenom. Under the action of light and atmospheric oxygen sterkobilinogena spontaneously transformed into stercobilin. Stercobilin - pigment stool, which gives it a certain color. In the absence of it in the stool stercobilin discolored (color clay).

Reactions to spend stercobilin when a patient unpainted stool.

The reaction with mercuric chloride (Schmidt). Sulem (7 g) dissolved in 100 ml of distilled water under heating. After cooling, the solution was passed through a paper filter. A small amount of feces ground in a mortar with 4.3 ml of the reagent to the consistency of the liquid slurry, poured into a petri dish and allowed to stand for 18 20 no. In the presence of stercobilin cal gets pink, color intensity depends on the pigment content. In the presence of bilirubin in the feces unchanged its color can be green through the formation of biliverdin.

To identify stercobilin can also be used reaction with zinc acetate. Quantification sterkobilina produce via spectroscope.

Average content stercobilin in the daily amount of feces 2- 6 g / l (200-600 Mg%).

Determination stercobilin in the daily amount of feces is important to differentiate parenchymal, mechanical and hemolytic jaundice. In hepatocellular jaundice, content in feces dropped stercobilin, hemolytic - increased, when obstructive jaundice stercobilin may be completely absent.

The content in the feces bilirubin was determined by reaction of Fouche. To prepare the reagent take 25 g trichloroacetic acid, 100 ml of distilled water 10 ml 10 % ferric chloride.

Feces was triturated with water in a ratio of 1 : 20 and added dropwise reagent Fouche (but not more than the volume of the diluted stool). In the presence of bilirubin appears green or blue color.

The reaction with mercuric chloride and reveals the content of bilirubin in the feces, but is less sensitive.

Normally, the bile entering the colon by the action of bilirubin bacterial flora is completely restored in sterkobilinogena and stercobilin. Therefore, when standing in the air cal dark. Unchanged bilirubin appears in the feces and in the increased peristalsis, Consequently, rapid evacuation of chyme from the intestines, which is why he does not have time to fully recover. Bilirubin is also found in the feces after ingestion of antibiotics and sulfa drugs, suppressive activity of the intestinal flora. In infants unchanged bilirubin is a normal part of the feces.

The protein and mucin in the feces was determined by Sample-Triboulet Vishnjakova. The method is based on illumination of the liquid as a result of adsorption of particles of feces coagulated protein and mucin. As reagents are used a saturated solution of mercury dichloride or 20 % trichloroacetic acid solution, 20 % acetic acid solution and distilled water.

Lump of feces (1,5 g) ground in a mortar with a small amount of distilled water, then add water to volume 50 ml (3 % emulsion). If loose or watery stools, it is diluted in half. Divorced feces poured roughly equal to three tubes (by 15 or 7,5 ml). The first of them is added 2 ml of a saturated solution of mercury dichloride or 2 ml 20 % trichloroacetic acid solution; the second - 2 ml 20 % acetic acid; a third, control,- 2 ml distilled water. The tubes were vortexed and left at room temperature for 18 24 no, and then take into account the results of. With full enlightenment of the supernatant reaction considered strongly positive (+++), with considerable enlightenment - positive (++), with a small prosvetlenii- weakly positive (+), when turbidity, with the same control tube,- Negative (-).

Awakening in the first tube indicates the presence of whey protein, the second - the presence of mucus (mucin).

Normally nucleoproteids food with feces are not allocated. When excluding the accelerated evacuation of the bowels protein bodies, obnaruzhivaemыe in Calais, likely, tissue origin. They point to the presence of inflammatory and ulcerative processes, associated with the destruction of the cells of the intestinal wall and tissue fluid exudation. In diseases of the intestines of this reaction is emphasized, and more valuable in the diagnostic against a positive reaction. The negative reaction can be observed in the presence of inflammation, if the stool in the colon are long, which contributes to bacterial breakdown of proteins.