Gregersen's reaction (benzidine test) is an analysis of feces aimed at identifying hidden blood from the organs of the gastrointestinal tract. What diseases can this study be prescribed for? How to prepare for it, and what can affect the result? How to decipher the received fecal analysis? Consider in detail in this article.
Gastrointestinal bleeding
Almost any disease of the gastrointestinal tract affects bowel movements and feces. Strong internal bleeding in the organs of the gastrointestinal tract so change the appearance of the bowel movements and their consistency that it is not difficult to make a diagnosis. So, black, tarry stool is also called "melena". Outwardly, it resembles feces after the use of activated carbon, but the hallmark is the consistency: it is more sticky. This condition indicates the presence of blood in the stomach. It acquires a black color due to a reaction with hydrochloric acid.
The second option: stool with "ordinary" blood. The red color of blood in this situation characterizes the fact that it passed the stomach, that is, bleeding is within the intestines. Also, scarlet, bright blood on toilet paper immediately after defecation is a sign of hemorrhoids, anus cracks or damage to the walls of the rectum due to too dry feces.
In certain cases, a Gregersen reaction to occult blood is performed. But why? The thing is that the human eye does not recognize the emitted milliliter of blood, but with the help of laboratory research methods it will be possible to determine it.
What pathologies does hemoglobin in feces occur in?
The presence of occult blood is determined by the reaction of Gregersen. It is carried out by determining the changed 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 (ulcer can bleed).
- Helminthiasis (helminths damage the intestinal wall).
- Malignant tumors of the stomach, intestines, esophagus.
- Varicose veins of the esophagus.
- Intestinal tuberculosis.
- Ulcerative colitis.
When is a Gregersen test prescribed?
The benzidine test does not belong to typical tests like a general urine test and a clinical blood test. This study should have indications or symptoms that will push the doctor to his appointment. These include:
- Gastrointestinal symptoms: abdominal pain, stool disorders, heartburn, nausea, changes in appetite.
- Unmotivated weight loss.
- The presence of peptic ulcer of the stomach and duodenum (to identify its bleeding).
- Diagnosis of tumors of the gastrointestinal tract.
Preparation for the study and the 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 outcome of the study.
The norm is daily loss of blood along with feces up to 1 ml, but this indicator can vary depending on the usual diet: for lovers of half-baked steaks, this indicator can be increased. That is why for more accurate indicators the patient is given several recommendations:
- Do not eat meat, fish, hemoglobin-rich foods (liver, heart), tomatoes for three days.
- Be careful when brushing your teeth. If there are diseases accompanied by bleeding of the gums, then hygiene should be carried out more carefully and in no case should swallow blood.
- Do not conduct research after manipulations on the intestines (including an enema).
- It is forbidden to take drugs that stain stool (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, one must adhere to the following rules: before collecting the biological material for the study, you should cover the entrance to the vagina with a cotton swab (or introduce a normal one), thoroughly wash the external genital organs and only after that carry out the collection.
Collection rules
Before collecting feces for Gregersen's reaction, you should buy or find a small clean and dry container with a lid. The fence should be made in the morning and immediately deliver the material for analysis. This is best done within 20-30 minutes.