Gregersen's reaction (benzidine test) is an analysis of feces aimed at detecting latent blood in it from the organs of the gastrointestinal tract. For what diseases can this study be prescribed? How to prepare for it, and what can affect the result? How to decipher the received analysis of feces? Consider in detail in this article.
Bleeding in the organs of the gastrointestinal tract
Almost any disease of the gastrointestinal tract is reflected in defecation and feces. Severe internal bleeding in the gastrointestinal tract changes the appearance of stools and their consistency so much that it is not difficult to make a diagnosis. So, black, tarry stools are also called "melena". Outwardly, it resembles feces after using activated charcoal, but the distinguishing feature is the consistency: it is more sticky. This condition indicates the presence of blood in the stomach. It acquires a black color due to the reaction with hydrochloric acid.
Second option: stool with "normal" blood. The red color of the blood in this situation characterizes the fact that it has passed the stomach, that is, the bleeding is within the intestines. Also, scarlet, bright blood on toilet paper immediately after a bowel movement is a sign of hemorrhoids, anal fissures, or damage to the walls of the rectum due to too dry feces.
In certain cases, the Gregersen test for occult blood is carried out. But why? The thing is that the released milliliter of blood is not recognized by the human eye, but with the help of laboratory research methods it will be possible to determine it.
In what pathologies does hemoglobin occur in feces?
The presence of occult blood is determined by the Gregersen reaction. It is carried out by determining altered hemoglobin in the feces, since the red blood cells themselves may not be detected microscopically, but the doctor suspects internal bleeding or diseases of the gastrointestinal tract, accompanied by blood leakage.
These include:
- Peptic ulcer of the stomach and duodenum (the ulcer may bleed).
- Helminthiases (helminths damage the intestinal wall).
- Malignant tumors of the stomach, intestines, esophagus.
- Esophageal varicose veins.
- Intestinal tuberculosis.
- Ulcerative colitis.
When is a Gregersen test ordered?
Benzidine test is not a typical test like urinalysis andclinical blood test. There must be indications or symptoms for this study, which will prompt the doctor to prescribe it. These include:
- Gastrointestinal symptoms: abdominal pain, stool disorders, heartburn, nausea, appetite changes.
- Unmotivated weight loss.
- Presence of peptic ulcer of the stomach and duodenum (detect its bleeding).
- Diagnosis of tumors of the gastrointestinal tract.
Preparation for the study and rules for passing the analysis
When deciphering the analysis of feces, blood is determined even with a slight blood loss of about 2 ml. So, even bleeding gums can affect the result of the study.
The norm is the daily loss of blood along with feces up to 1 ml, but this figure may vary depending on the usual diet: for lovers of half-baked steaks, this figure may be increased. That is why, for more accurate indicators, the patient is given several recommendations:
- Do not eat meat, fish, foods rich in hemoglobin (liver, heart), tomatoes for three days.
- Be careful when brushing your teeth. If there are diseases accompanied by bleeding gums, then hygiene should be carried out more carefully and in no case should you swallow blood.
- Do not conduct research after manipulations on the intestines (including enema).
- Do not take drugs that stain feces (iron preparations, activated charcoal),laxatives and drugs that affect intestinal motility.
- Women are not recommended to conduct this study during menstruation, so that there are no false indicators when deciphering the analysis of feces. In the case when the study cannot be postponed, you must adhere to the following rules: before collecting biological material for research, you should cover the entrance to the vagina with a cotton swab (or insert a regular one), thoroughly wash the external genital organs, and only then carry out the collection.
Collection rules
Before collecting feces for the Gregersen reaction, you should buy or find a small clean and dry container with a lid. The sampling should be done in the morning and immediately deliver the material for analysis. This is best done within 20-30 minutes.
