Blood in emptying can be hidden and completely invisible to the eyes. For its recognition, an immunochemical analysis of feces for occult blood and blood test will be required. The presence of occult blood in the feces indicates a slow and gentle bleeding in the digestive tract, which appears periodically. Most often, this type of blood loss occurs without unpleasant symptoms, which does not reveal the nature and location of the bleeding. Each section of the digestive system can be a site of hidden bleeding. In this case, the doctor can diagnose both benign formations that are harmless to the body (for example, hemorrhoids), and serious ones - tumor.
Features of the procedure
An analysis of feces by the immunochemical method is prescribed to the patient if a latent form of bleeding in the digestive system is suspected. According to medical standards, in 1 gram of feces of a healthy person there is no more than 2 mg of hemoglobin, that is, at least 2 ml of blood comes out with feces during one day. If there is bleeding of different intensity in the gastrointestinal tract, the color of feces changes greatly.
If the source of bleeding is high (the duodenum, small intestine), the stool becomes dark, tarry, and with low localization, blood in the stool can be seen at a glance. If blood discharge in the emptying is, but not visible, then this condition is classified as hidden. In this case, it is possible to determine the ailment only in the laboratory by the immunochemical analysis of feces for occult blood:
- a test with benzidine (in another way Gregersen's reaction) or with guaiac gum;
- quantitative immunochemical method.
Detection in the stool of blood indicates the presence in the patient of diseases of the intestines and stomach, which lead to a violation of the integrity of the mucous membrane of organs.
Causes of bleeding in the digestive tract
The appearance of bleeding from the organs of the gastrointestinal tract is promoted by such diseases as:
- peptic ulcer of the duodenum and stomach;
- polyps, the presence in the gastrointestinal tract of formations of a malignant and benign nature;
- nonspecific ulcerative colitis;
- Crohn's disease;
- the presence of cracks in the anus;
- hemorrhoids;
- diffuse family polyposis.
It is important for patients who have one of the aforementioned ailments to regularly take an analysis to check for hidden blood in their bowel movements.
How often should an analysis be taken?
An analysis of feces for occult blood by an immunochemical method is prescribed to people older than 50 years of age annually, it is included in the list of early diagnosis of malignant neoplasms of the intestine, the frequency of lesions of which at this particular time period significantly increases.
If hidden blood is detected in people older than 50 years, doctors prescribe them a number of additional diagnostics and subsequent treatment.
Benzidine test
The decoding of the immunochemical analysis of occult blood in the feces is the benzidine test (in other words, the Gregersen-Adler reaction). Such a reaction is used to determine the impurity of blood in any biological material of a person (gastric juice, feces or urine). If there is blood in the test material, when the appropriate reagent is introduced, its color changes to a bright green or blue hue.
An analysis of this type should be carried out only after preliminary preparation of the patient, since due to the large amount of hemoglobin in meat food, some vitamins and other components, a false result can be obtained.
Diet food
To avoid such results and further problems, you need to adhere to a special diet. 72 hours before the laboratory examination, food of animal origin (meat, poultry and fish), as well as some vegetables (zucchini, horseradish, cucumbers, cabbage, broccoli and tomatoes) should be removed from the diet.
In a newborn baby, maternal nipple cracks can lead to incorrect research results. At the time of breastfeeding, the cracks bleed, and the baby swallows the blood secreted along with the milk.
Before the analysis, the following products should be included in your diet:
- dairy products (kefir, cottage cheese, milk, cheese, feta cheese and fermented baked milk);
- from cereals rice, oat and wheat are allowed;
- vegetables (carrots, white cabbage and potatoes);
- fruits;
- tea of weak tea leaves, mineral water without gas;
- sweet confectionery products.
Features of occult blood analysis
Old methods for detecting hidden blood in feces, including a benzidine test, give a reaction not only to human hemoglobin, but also to animal hemoglobin found in meat products. As a result of such examinations, it is not always possible to determine what indicates a positive result - hidden bleeding or a lot of meat in the diet.
An immunochemical blood test eliminates this development of events and gives a reaction exclusively to human blood. This suggests that before the procedure, the patient does not need to follow a diet.
How to collect material for analysis?
Preparation for immunochemical analysis of feces for occult blood consists in understanding the basic rules of assembly of the material. 3 days before the procedure, you should stop taking medicines with iron and bismuth in the composition, and the day before the delivery of the material - vitamin C (ascorbic acid) and Aspirin (acetylsalicylic acid).
72 hours before the examination, any treatment and diagnostic procedures that somehow affect the organs of the gastrointestinal tract should be discontinued, that is, colonoscopy, sigmoidoscopy, and radiopaque examination of digestion should not be performed.
The day before the stool is checked, the patient should not brush his teeth, as a brush, especially with stiff bristles, can accidentally injure gums and cause bleeding, which will give false results.
A bowel movement for examination should be taken only after an independent bowel movement. It is forbidden to use laxative drugs or an enema before the examination, as this will distort the result.
It is also important to make sure that urine or vaginal discharge does not accidentally get into the collected material. To do this, it is recommended to urinate before defecation, and then wash and dry the perineum with a simple towel. When defecating, straining too much is not recommended.
Immediately after defecation, you should collect material from 3-4 sections of feces and move them into a disposable container with a lid and spatula, which can be taken in a laboratory or purchased at a pharmacy. Only 1/3 of the container volume is enough for the examination. The collected material is delivered to the laboratory as soon as possible.
Decoding of the research results
In the decoding of the immunochemical analysis for occult blood, there should normally be no blood. Incorrect readings can be obtained in the following cases:
- failure to follow a diet (when using a benzidine test);
- collecting analysis during menstruation;
- nosebleeds;
- severe bleeding gums.
The immunochemical method can lead to a false negative result. Most often this happens when unchanged red blood cells are found in the feces, for example, with bleeding cracks in the anus or due to hemorrhoids.
What diseases does the blood in the stool indicate?
If the patient carefully prepared for the procedure and complied with all the rules, and also ruled out all factors that could adversely affect the reliability of the biochemical analysis, then the detection in the stool of blood may indicate the presence of diseases of the gastrointestinal tract in the patient, which led to deformity of the mucous membranes shells:
If the doctor doubts the reliability of the results obtained after the procedure, then appoints a second analysis. An immunochemical analysis of feces for occult blood can be performed in Voronezh.
Additional rules for collecting feces
Only compliance with these rules guarantees the patient an accurate result of the analysis of feces:
- Biomaterial is collected in the morning.
- The collection should be carried out so that the stool does not accidentally fall into the water. It is best to collect it in a clean and dry container or close the toilet with a film so that the stool is directly on it.
- It is forbidden to collect material for analysis within 3-5 days after the end of menstruation, with hemorrhoidal bleeding. Aspirin, alcohol, and some anti-inflammatory drugs can cause severe irritation of the intestines (including the colon) and cause hidden bleeding. Sample collection should be carried out using a special can and spatula, from 3-4 different points of feces.
- If the diagnosis requires three stool samples at once, then they should be collected from three bowel movements, even on the same day.
- The collected material must be delivered to the clinic within the next three hours.
- If necessary, provide three samples, each sample should be stored in a refrigerator, and then taken to the laboratory at a time.
- After collecting the stool for occult blood can be checked in the next 7 days. It is important to remember about the requirements of a medical institution.
The test for occult blood in fecal massage is considered the main one when screening colorectal cancer for the reason that the tumor formation develops without pronounced symptoms, but can be detected and cured in a timely manner even with minimal and periodic bleeding.
Most often, latent blood in stool is a clinical picture of anemia (microcytic anemia). For this reason, in the presence of symptoms of anemia, a person will have to undergo a whole range of examinations (gastroscopy, colonoscopy). Immunochemical analysis of feces for occult blood in Invitro is the easiest and fastest.
Treatment of diseases of the digestive tract
Treatment of the gastrointestinal tract will include following a strict bed rest, eliminating physical activity and emotional outbursts. This will help prevent increased bleeding and its resumption. If possible, an ice bladder should be placed on the area of the body near which the diseased organ is located (in case of bleeding from a stomach ulcer - on the upper abdomen, from a duodenal ulcer - on the right side of the abdomen).
If blood escapes from the varicose veins of the esophagus, endoscopic coagulation (cauterization of the source of bleeding) is prohibited, a Blackmore probe (a rubber tube passing into the esophagus and stomach) is used for treatment. Special balloon-shaped extensions are installed on it, which, after insertion into the probe organ, are filled with air and compress the dilated veins from which the blood comes.
Blood lost during an illness can be restored by intravenous administration of blood-replacing solutions. If the blood loss is too strong, a donation of the components of the donated blood is necessary. Intravenous and intramuscular administration of medicines with iron is required to get rid of anemia (lack of blood in the body).