Analysis for occult blood in the intestine. Preparation for the analysis of occult blood in the stool. Occult blood test

Stool examination provides information about the patient's health. This method helps to identify various diseases and disorders in the body.

If the patient is prescribed a stool sample, a few days before the procedure, one should go on a diet - this will allow obtaining reliable results during the analysis.

Nutrition in preparation for diagnosis

In this case, it is necessary to stop consuming apples, white beans, cucumbers, spinach, cauliflower, horseradish, meat and fish products. Tomatoes, bell peppers and green vegetables are also prohibited.

Alcohol, sweet carbonated water, coffee, black tea are prohibited from drinks. Pure non-carbonated water is allowed.

Patients are allowed to consume potatoes, cereals, dairy products. You need to eat in small portions without overeating. It is important to give up frying; instead, products are boiled, stewed or baked.

Basic principles

Basic principles of the method:

Dishes are prepared by boiling, stewing, baking or steaming. Frying is strictly prohibited: such food can negatively affect the results of the analysis. The daily calorie content should not exceed 2200 kcal, the weight of the dishes should be 2.2-2.5 kg.

You need to eat every two hours, but in small portions... We have 5-6 meals a day. The program lasts from 3 to 5 days - this is enough to prepare the body for the test.

Its effect on the body

The technique is aimed at preparing the body for the analysis. It is cleared of harmful substances, components that can negatively affect the result of the procedure are removed.

The human condition will improve significantly... The exclusion of heavy-to-digest, high-calorie foods from the menu can lead to a decrease in body fat, a person will lose a little weight.

Pros and cons of the method

The benefits include:

High efficiency.
Beneficial effect on the digestive system.
You don't need to starve.
Assistance in obtaining reliable analysis results.

However, each diet has not only advantages, but also disadvantages: the patient is allowed to consume very few products. They can get bored in a few days.

Most of the usual dishes are excluded from the menu. The diet is not easy for all patients, but it is effective, so such restrictions are understandable..

This technique has no contraindications, but in the presence of chronic diseases, the doctor can correct the diet, add or exclude certain foods. It is necessary to consult a doctor.

Sample menu

In order not to make mistakes in nutrition, you need to familiarize yourself with the menu compiled by specialists:

The diet is usually followed for three days. For breakfast, it is better to eat porridge or low-fat cottage cheese. For lunch, mashed potatoes, a stew of non-green vegetables, or boiled rice are suitable.

For dinner, fruit salads, low-fat yogurt, or cottage cheese are acceptable.

When drawing up the menu, you should remember about the lists of prohibited and allowed products.

Allowed foods are very few, and they are included in the diet. The focus is on low-fat dairy products, cereals and non-green vegetables.

List of approved products

During the diet, you can consume:

Dairy products - milk, kefir, low-fat cottage cheese.
Porridge - rice, buckwheat.
Vegetables - potatoes, beets, carrots.
Fruits - peaches, persimmons.
Drinks - jelly, compote, berry juice.

It is allowed to add a little butter to the dishes. For lunch or dinner, you can eat a slice of bread. The main thing is not to eat buns and flour products, they are prohibited. You can add a little sugar to tea, but you cannot eat sweets themselves..

Dried fruit compotes have a beneficial effect on the patient's condition. They are consumed throughout the day. This is a great addition to lunch or dinner or a snack.

What should not be consumed

Patients need to refuse the following:

Green vegetables and fruits.
Meat and fish.
Seafood.
Nuts.
Legumes.
Dairy products - fermented baked milk, sour cream, yogurt.
Drinks - alcohol, sweet carbonated drinks, coffee.

It is necessary to abandon not only the named food, but also from spices, flavorings, sweeteners. Smoked products, semi-finished products, salinity are also prohibited.

For the results to be reliable, it is necessary to abandon cereals such as barley, millet, wheat... They can negatively affect the diagnosis.

During the diet, experts advise to strictly adhere to the menu, not to fall for prohibited foods. You cannot starve and overeat. You need to eat every two to three hours, avoiding the feeling of heaviness in the stomach.

If the patient does not have kidney problems, drink 1.5 liters of water per day.... This will help prepare the body for the procedure.

If a person takes any medications, they are abandoned during the diet. They can influence the result of the analysis.

Intense sports training is also not recommended; walks in the fresh air are acceptable.

The technique is often used due to its high efficiency. Its main principles include:

During the day, a person consumes mainly dairy products, in small quantities - fruits and vegetables.
It is allowed to consume cottage cheese, milk, kefir.
Porridge is boiled in milk, casseroles are prepared from cottage cheese.
Add sugar to dairy products, sweet syrups are prohibited.

The program lasts 3-5 days, the doctor can tell exactly how long this nutrition is. In addition to milk, it is allowed to drink water, compotes, jelly and berry decoctions.

You can add fruits to milk porridge and cottage cheese, but not green. Peaches, pears, persimmons are optimal. This diversifies the diet, the person will tolerate the diet more easily.

Before donating feces for occult blood, a diet is necessary: it helps to prepare for the analysis, cleanses the body, and has a beneficial effect on the human condition.

Knowing the principles of such nutrition, a person will perfectly cope with preparing the body for analysis, and the results will be reliable.

In contact with

It is known that by analyzing blood we can determine chronic anemia in a patient. Its positive confirmation in the form of a low content of red blood cells - erythrocytes, a decrease in hemoglobin indices indicates the presence of blood loss. Moreover, bleeding can be sluggish, periodic and latent. And when it is not possible to establish the obvious sources of bleeding, a special analysis of feces for blood was invented.

Taking an analysis, conducting a study, how to donate feces for occult blood?

Indications for analysis

An analysis is needed in order to determine if there is damage to the organs of the gastrointestinal tract. If the integrity of the mucous membrane of at least one organ is violated, this will be seen from the results.

The reason for the analysis may be:

Severe bowel disease.
Ulcer.
Colitis.
Polyps.
Anemia.
Poor appetite.
Abnormal stool.
A sharp change in weight downward.
Frequent constipation.
Heartburn.
Sharp pain in the abdomen.
Constant nausea.

In addition, feces for occult blood are taken if there is a suspicion of cancer or a benign neoplasm.

Recall that a direction for analysis can be taken from a surgeon, therapist, oncologist or gastroenterologist.

What do you need to know about research?

At the present stage, everyone who is tested for occult blood needs to have at least general information on this matter.

The fresher the sample, the more accurate the results will be.
Before taking samples, you need a simple preparation for several days.

The daily amount of dense excrement is approximately 200 grams. Much more comes out with pathological processes of the gastrointestinal tract, less - with malnutrition, the use of protein foods, problems with defecation.

By the form, you can understand if there are deviations in the work of the intestines. In a healthy person, feces have a sausage-like shape of medium density, brown in color. When disturbed, the excrement can be very dense or liquid, lumps or in the form of a tape. In severe pathologies, not only the appearance changes, but also the composition, smell, various impurities appear.

Normal feces can contain particles of undigested food - the norm is - peel of fruits or vegetables, cartilage or tendons.

If mucus or blood is visible to the naked eye, this indicates a colon disease.

How to properly collect material and donate feces for occult blood?

Almost all patients know how the medical staff should behave. However, few people remember that for patients there are also general recommendations regarding the delivery of any analysis, including feces. They are as follows.

Feces are collected after natural bowel movements... The use of enemas or laxatives is prohibited. It is not recommended to use it a few hours before sample collection, and special preparations for another 3-4 days. If this rule is violated, the analysis will not be accurate. However, this only applies when feces are donated for occult blood.

The accuracy of the results depends on the freshness of the material. It is considered ideal if the sample reaches the laboratory within 3-6.5 hours after its collection. This rule is not always easy to follow, however, some microorganisms live outside for only a few hours. Therefore, it becomes more and more difficult to get a complete picture over time. It is desirable to pass the analysis before 10 hours.

3-4 days prior to the delivery of samples, special preparation is needed - adherence to a diet. You can not eat a lot and those foods that cause discomfort in the stomach and intestines. Avoid foods that stain your excrement, such as beets, herbs, and some fruits.

If possible, do not take pharmaceutical preparations a week before collection of samples. The exception is those that are taken regularly for chronic diseases. This is due to the fact that some drugs color the feces in a different color or change the composition of the microflora. Also, do not do additional bowel tests using special enemas such as barium. It discolours the faeces and changes their structure.

Collect the sample in a special container with a spoon, you need to purchase it in advance. A few grams of material is enough to make an accurate analysis. In appearance - about a teaspoon.

The last rule applies to women. It is not recommended to collect material during menstruation, as blood can enter the faeces and spoil the results.

Diet before fecal occult blood test

A few days before sampling, a special diet is prescribed, which must be followed so that the analysis is correct the first time.

During this period, you cannot eat, we repeat once again:

Liver in any form;
Legumes;
Fish and meat dishes;
Apples and other fruits that affect the color of feces
Greens, in particular spinach;
Some vegetables: tomatoes, bell peppers, beets, hot horseradish.

Sample menu for one day:

Bread and butter, milk soup, some pears or peaches, can be canned in winter;
Mashed potatoes, 2 boiled eggs, milk jelly;
Yogurt without dye;
A glass of kefir or fruit.

The amount of food taken at one time should not exceed 300-400 grams. The same set of products with some correction and variations should be eaten for 2 more days.

Feces for occult blood: deciphering the results

The finished analysis is called a coprogram. First of all, the presence of blood, even in the form of individual cells, is not characteristic of feces. Therefore, a microscopic examination is carried out to find out if red blood cells are present in the excrement?

They can be there for several reasons: damage to the stomach and small intestine or the lower part, that is, the rectum, colon and anus. If the bleeding is heavy, the discharge is already noticeable - the feces will be black; in the case of minor damage, it is difficult to determine anything without special studies.

Damage to the lower digestive system is noticeable due to the presence of bright red impurities. Since some products and drugs can have a similar effect, you need to undergo a diagnosis, that is, donate feces.

This analysis will show if there are problems in the upper part of the food system, in the case of the presence of red blood cells in the material submitted for research. There are no special standards for this, even the smallest content of blood particles in the feces is enough.

If the gums or nasal mucosa are bleeding, the test will be positive. Therefore, careful preparation for the procedure is needed, and the day before it is not recommended to brush your teeth and try to avoid various injuries.

An occult blood test is an opportunity to identify diseases that cannot be noticed when passing simple tests. The study reveals a variety of serious illness, which are characterized by damage to the alimentary tract. Including various cancers, Crohn's disease, ulcerative colitis and others.

An occult blood test is prescribed by the attending physician if suspicion of bleeding in the digestive tract... This problem can be a sign of many diseases, including cancer.

Oncological problems with the large intestine, already at the initial stage of manifestation, can cause constant slight bleeding. They appear due to the fact that neoplasms consisting of cancer cells often bleed and blood directly enters the large intestine.

In this case, blood in the stool can be detected using a routine test. But in rare cases, blood can only be detected when occult blood test.

A positive test result can be caused by the following diseases:

helminthiasis (infection with large helminths that can injure the intestinal wall);
polyposis (overgrowth of polyps in the intestine);
ulcer (inflamed intestinal microtrauma caused by bacteria);
inflammatory processes on the gastric mucosa and in the intestines;
hemorrhoids and hemorrhagic diathesis;
typhoid fever;
stomach pathology;
Crohn's disease;
neoplasms in the large intestine;
duodenal pathology;
cancerous tumors.

Decoding

Occult blood can only be detected by microscopic analysis or hemoglobin ( guaiac sample). It is allowed to use tests based on monoclonal antibodies that react to the presence of hemoglobin.

The high sensitivity of such tests allows them to be considered much better than conventional express methods.

It should be borne in mind that in some cases, a completely healthy person can also have a positive reaction, therefore, only specialists can accurately determine the violation.

Fine, the occult blood reaction must be negative.

If the reaction is positive, there is a suspicion of chronic pathologies associated with the gastrointestinal tract. This is usually damage to the mucous membrane.

In this case, blood can penetrate into the lumen of the large or small intestine, the stomach. At the same time, such a violation can be detected only with the help of an occult blood test.

Also, the reasons for a positive reaction can be:

colitis;
duodenal ulcer;
nonspecific ulcerative colitis.

But a false positive result is manifested if blood has entered the stomach from the oral cavity, when a person suffers from hemorrhoidal bleeding, hematuria, helminthic invasion, and others. Also, the reasons can be in strong tensions during bowel movements and with inaccurate delivery of feces for analysis during menstruation.

What if the test is positive?

In the event that the analysis is positive, it is necessary to undergo diagnostics. This should initially be a colonoscopy. This diagnosis allows you to see the exact location of the lumen in the lower intestine.

If necessary, you can take a biopsy, after which more accurate information will be obtained about the cause of occult blood in the feces.

If the reason for the appearance of this pathology was the development of a tumor, in the future you will have to consult an oncologist, as well as conduct magnetic resonance imaging.

Treatment

Treatment after revealing a positive test result, should only be discussed with a doctor.

In no case should you prescribe yourself medicines or use traditional medicine methods on your own, since they can cause even more harm to the body.

Positive analysis in infants and children under three years of age

Any change in concentration and color of stool in infants causes anxiety in parents. But with a single chair change, you shouldn't worry. But if the scarlet impurity in the feces manifests itself regularly, it is necessary to consult a doctor and be tested for occult blood in the feces.

A fairly common cause of blood in the feces is intolerance of the baby to cow's milk... Problems can arise even if milk is consumed by the mother of the child, who continues to breastfeed. Problems can also begin if the mother eats butter, sour cream, cheeses and other dairy products.

If the child is artificially fed, it is necessary to carefully select a mixture that does not contain cow's milk protein.

If the baby has a positive fecal occult blood test, the problem may be in inflammatory bowel diseases:

dysbiosis;
amoebiasis;
colitis;
dysentery;
balantidiasis.

An accurate diagnosis is established only based on examination and coprogram.

Another cause of occult blood in the stool can be an infection caused by the introduction of adult foods into the baby's food.

This problem may also be accompanied by vomiting, diarrhea, abdominal pain, high fever.

In older children (from two years old), a positive reaction to occult blood in the feces can be observed in case of problems in the large intestine - juvenile polyps... Such formations do not cause discomfort to the child and are not dangerous to his health. You can delete them if desired or necessary.

Content

Pathologies of the duodenum, stomach, esophagus may be accompanied by internal bleeding. Stool analysis helps to identify them at an early stage. The study reveals occult blood, which often becomes a sign of cancer.

What is occult blood in feces

Traces of blood in the excrement invisible to the human eye are called latent blood. They are found only when carrying out special tests to detect transferrin or hemoglobin. The study gives the most reliable results when identifying such pathological conditions:

duodenal ulcer, stomach;
helminths in a child;
intestinal tuberculosis;
blood diseases;
varicose veins of the esophagus;
Crohn's disease;
erosive esophagitis;
cirrhosis of the liver;
lynch syndrome;
hemorrhagic diathesis;
tumors;
polyposis;
inflammation of the tonsils, pharynx.

The analysis of feces allows you to identify at an early stage colorectal cancer, intestinal tumors. Positive test results are typical for such pathologies:

diverticula of the intestine, stomach;
erosive gastroduodenitis;
nonspecific ulcerative colitis;
damage to the mucous membrane of the digestive system.

When an occult blood test is prescribed

Doctors prescribe the patient a fecal examination when signs of diseases of the digestive system appear. The indications for the study are the following symptoms:

abdominal pain of unclear etiology;
false urge to defecate;
unreasonable loss of body weight;
diarrhea;
constipation;
hyperthermia;
nausea;
heartburn;
vomit.

Methods for detecting occult blood in feces

If there is a suspicion of internal bleeding, doctors use different methods for examining feces. They are distinguished by sensitivity, efficiency, the need for preparation, the definition of pathologies in various parts of the intestine. Occult blood diagnostic methods, their advantages and disadvantages:


Benzidine test	instant results; high sensitivity; availability; low price	required: thorough preparation; adherence to a strict diet; correct sampling of biomaterial
Immunochemical test	no nutritional restrictions required; high accuracy, sensitivity; efficiency; lack of reaction to hemoglobin in foods, medicines	not everywhere; high price; objectivity only with blood loss in the lower intestine (enzymes of the small intestine, stomach disrupt the reaction)
Guaiac test	availability; promptness	sensitivity only to large blood loss; high dietary requirements; the test is performed 6 times

Benzidine test

This analysis of feces for the detection of latent blood loss has a second name - the Gregersen test. The main reagent is benzidine, to which acetic acid and barium peroxide are added to increase the activity. The technique gives many false positive results - a reaction to nosebleeds, eating meat, medicines, bleeding gums.

Immunochemical test

Operative research reveals neoplasms in the colon at an early stage, reduces cancer mortality by 30%. Immunochemical analysis of feces for occult blood reacts only to human protein, does not require special preparation. It is characterized by high sensitivity and the following features:

Guaiac test

The sensitivity of the guaiac test depends on the concentration of hemoglobin. If its content is more than 2 mg per gram of feces, the result is positive in 90% of cases. The test diagnoses bleeding in any part of the digestive system. The analysis has the following specificity:

Study preparation rules

To get an accurate test result, proper preparation is essential. The process begins a week before the analysis and includes the following activities:

Time to research	What needs to be done
	exclude laxatives; do not use enemas	affect intestinal motility
	stop taking: preparations containing iron; non-steroidal anti-inflammatory drugs; Aspirin; vitamin C	change the color of feces
	do not have anal sex	possible damage to mucous membranes
	remove from the diet: green onions; apples; spinach; broccoli; pepper; beets; tomatoes; garlic	include iron, pigments
	exclude fish, meat, offal (for guaiac or benzidine test)
	the last time to carry out before stool analysis: X-ray studies; colonoscopy; sigmoidoscopy	contrast agent can distort the result; special devices often damage mucous membranes
	do not eat hard food; brush her teeth	possible injury to the gums, blood entering the feces

Features of preparation for the Gregersen test

To eliminate the error of the results for this technique, it is important to strictly follow the diet. Gregersen's occult blood reaction is sensitive to iron, pigments from food. It is necessary to postpone research for a while under the following circumstances:

the presence of blood in the urine (hematuria);
menstruation in women;
hemorrhoids with bleeding;
periodontal disease;
indigestion (dyspepsia);
tears, damage from anal sex.

An important role is played by the correct sampling of material for analysis. The following conditions must be met:

hygiene of the genitals, anus;
collect feces in the morning, before breakfast;
the ingress of water, urine is unacceptable;
you can not take biomaterial from the toilet (you need to put an oilcloth);
fragments must be from three places;
put feces in a special sterile container;
deliver to the laboratory within two hours.

Deciphering the analysis of feces for occult blood

The interpretation of the research results is the responsibility of the doctor. An immunochemical test is considered the most accurate, but it is not performed in all laboratories. It takes 1-3 days to conduct and decipher the analyzes. Experts recommend, upon receipt of positive and negative results, to conduct an additional re-examination of feces for the presence of latent bleeding and diagnosis using instrumental methods.

Negative result

If a small amount of blood enters the intestines, enzymes in a healthy person decompose it. The norm is considered to be 0.2 mg of hemoglobin per gram of feces. A negative result confirms the absence of bleeding in the body, dangerous diagnoses, or requires re-conducting when the patient shows signs of pathologies.

Positive

If a patient suspects latent bleeding, a positive test result is possible. Often, it indicates an early stage of diseases associated with damage to the mucous membranes:

colorectal cancer;
peptic ulcer;
intestinal tuberculosis;
tumors of the digestive system;
helminthiasis;
pathologies of the veins of the esophagus;
hemorrhoids.

A positive reaction to occult blood in a child

When analyzing feces in children, signs of latent bleeding are sometimes revealed. The reason for the positive reaction depends on the age:

False positive and false negative results

Often, fecal studies for the presence of hidden blood loss give ambiguous results - false negative, false positive. In this case, repeated tests are required, additional diagnostics are carried out. A false positive answer is possible in such cases:

lack of preparation for research;
the presence of nosebleeds;
violation of the recommended diet;
use of medications;
bleeding gums.

The reason for a false negative result may be a violation of the analysis technology, low-quality reagents. If there is a suspicion of the development of pathologies, a second study is required. A false negative result occurs in such situations:

limited amount of biomaterial provided for testing;
uneven distribution of blood particles in the feces;
the presence of tumors, polyps that bleed sporadically.

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In order to determine the state of the human body, you need to undergo an examination and hand over some materials to a laboratory for research. There are many types of tests, one of them is feces for occult blood. The preparation takes several days.

Feces collection for occult blood: indications

The reason for the analysis may be:

In addition, feces for occult blood are taken if there is a suspicion of cancer or a benign neoplasm.

You can take a referral for analysis from a surgeon, therapist, oncologist or gastroenterologist.

What do you need to know about research?

At the present stage, everyone who is tested for occult blood needs to have at least general information on this matter.

The fresher the sample, the more accurate the results will be.

Before taking samples, you need a simple preparation for several days.

Normal feces may contain particles of undigested food - the norm is the peel of fruits or vegetables, cartilage or tendons.

If mucus or blood is visible to the naked eye, this indicates a colon disease.

How to donate feces for occult blood correctly?

Feces are collected after natural bowel movements. The use of enemas or laxatives is prohibited. It is not recommended to use it a few hours before sample collection, and special preparations for another 3-4 days. If this rule is violated, the analysis will not be accurate. However, this only applies when feces are donated for occult blood.

Collect the sample in a special container with a spoon, which must be purchased in advance. A few grams of material is enough to make an accurate analysis.

The last rule applies to women. It is not recommended to collect material during menstruation, as blood can enter the faeces and spoil the results.

Diet before fecal occult blood test

A few days before sampling, a special diet is prescribed, which must be followed so that the analysis is correct the first time.

During this period, you can not eat:

Sample menu for one day:

Bread and butter, milk soup, some pears or peaches, can be canned in winter;
Mashed potatoes, 2 boiled eggs, milk jelly;
Yogurt without dye;
A glass of kefir or fruit.

The amount of food taken at one time should not exceed 300-400 grams. The same set of products with some correction and variations should be eaten for 2 more days.

Feces for occult blood: transcript

The finished analysis, interpretation, is called a coprogram. First of all, the presence of blood, even in the form of individual cells, is not characteristic of feces. Therefore, a microscopic examination is carried out to find out if red blood cells are present in the excrement?

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Is it so important how to collect materials for research?

It is important to understand that everything related to the conduct of medical procedures must be systematic and orderly. For this, there are many rules and recommendations, for example, how to take certain medications and when is the best time to get tested.

The same is true for the delivery of feces for analysis. With routine microscopic examinations, you can get an overall picture of your health. However, fecal occult blood test is different from other laboratory tests.

Why get tested for occult blood

It so happens that a person is not worried about anything, and there are no noticeable changes in the work of the alimentary canal. Why do you need to take such an analysis?

The analysis of feces for occult blood allows you to detect some serious pathologies in the early stages. For example, for many years in a row, there may be minor bleeding in the human body that does not make itself felt. The patient does not have any pain or deterioration in well-being.

At the same time, such violations may indicate pathologies in such organs:

rectum;
stomach;
spleen;
intestines;
liver.

Latent blood in the feces can be detected in hemorrhoids and thrombophlebitis of large internal veins. All this requires careful diagnosis and a sensitive approach from the attending physician.

Reasons for the unreliability of the analysis results

In some cases, the result of the analysis can be questioned. Most often this is due to the fact that the biomaterial for the study was not collected in accordance with the rules.

Blood can be detected in such cases:

blood from menstrual flow has entered the feces;
due to nosebleeds, it entered the esophagus, and then into excrement;
from the cracked lips, fragments of blood entered the body.

How to get tested for occult blood correctly?

For the result of the analysis to be reliable, it is important to properly prepare for its delivery. It is not only about how to properly collect feces for research, but also what can be eaten for reliable results.

Preparing for the test in two weeks

If you have received any antibiotic treatment, you should stop it at least two weeks before the test. If this is not possible, the delivery of biomaterials should be postponed. Two weeks should elapse between the last antibiotic intake and the test.

Preparation measures one week before collection of biomaterial

In about a week, you should stop taking such medicines:

vitamins;
aspirin;
any blood thinners;
preparations containing iron in any form;
non-steroidal anti-inflammatory drugs.

What is important to do three days before the procedure

For such a period before the planned date, it is important to remove such nutritional components from your diet:

meat products;
a fish;
liver;
apples;
cucumbers;
green onions;
some types of beans;
spinach;
Bell pepper;
cauliflower.

Two days before analysis

In no case should you allow the biomaterial for analysis to be taken less than two days after the X-ray examination. This can affect the results.

You should also not take activated carbon and bismuth. These drugs change the color of the stool, making it difficult to diagnose. It is worth refraining from setting candles, as this can change the chemical composition of the feces.

What women need to consider

It is not recommended to take such an analysis during menstruation. Blood from the vagina can penetrate the test material and distort the conclusions. If an occult blood test is urgently needed, then a tampon should be used.

The importance of hygiene when collecting stool

Do not think that if the feces itself contains a large number of bacteria, then hygiene is not so important. Small fragments of urine or chemicals from laundry and clothing can interfere with the accuracy of the results.

First you need to urinate and wash yourself well with warm water and soap. Then you need to defecate in a clean, dry container. You should not do this in the toilet, as there may be a large number of microbes, the ingress of which will distort the results of the analysis. For these purposes, a vessel or pot is suitable. If these items are not in the house, you can use a clean bag or film, with which you can then take part of the sample.

What to bring the analysis of feces?

Pharmacies have a solution to this problem. If you do not know how to bring biomaterial to the laboratory, purchase special containers. Don't fill it out completely. The third part will be enough for research.

Is all stool suitable for examination?

If the stool was obtained by taking laxatives or using an enema, it cannot be used for analysis. This shows that only material that was obtained spontaneously is suitable for laboratory research.

It is best to use fresh stool. The ideal situation is when it is assembled just before delivery to the laboratory. If it is evening feces, it is better to place it in the refrigerator, where the storage temperature will not exceed six degrees.

In order for the results of the analysis to be reliable, it is important to submit the biomaterial exactly according to the rules. This will help your attending physician to detect latent diseases in a timely manner and begin treatment at an early stage.

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What is the research for?

Analysis of feces for occult blood shows the presence of invisible hemoglobin and red blood cells. The study is very valuable in determining intestinal bleeding in the early stages, when it is not yet noticeable to the eye. In what cases is a fecal occult blood test indicated? Below are the main factors:

Pain or discomfort during or before bowel movements.
Any impurities in the stool (mucus, foam).
Changes in stool character. It has become liquid or, on the contrary, too dense.
In the feces, traces of blood are periodically noticeable.
Decreased appetite or significant weight loss.
Pain in the abdomen of any location.
The presence of symptoms such as heartburn, nausea, vomiting, iron taste in the mouth.
Periodic unreasonable increase in body temperature.
Annually as a screening examination for patients over 40 years of age. It is carried out for the early detection of colon tumors.

If you have any of the above symptoms, it is recommended to donate feces for an occult blood test.

Preparation for the analysis of feces for occult blood, what is it for?

Patient preparation is necessary only in the case of analysis by chemical reactions (benzidine, guaiac samples). These samples often give false positive reactions, for example, for animal hemoglobin found in meat foods, or for chemicals in food and vitamins.

To date, there is an analysis that does not require special preparation of the patient. This is a fecal occult blood immunochemical test. It is based on the interaction of antibodies only with human hemoglobin, so the analysis is more specific and sensitive than standard chemical samples.

It should be borne in mind that the analysis is reliable only in relation to bleeding from the lower intestine (colon and rectum). In the upper sections, hemoglobin is significantly affected by digestive enzymes and destroyed. Therefore, after the study, with a positive result, it is recommended to undergo an additional examination (colonoscopy, for example).

How do I prepare for the analysis?

Diet before the analysis of feces for occult blood. For three days (72 hours), food of animal origin (meat, fish) must be excluded from the diet. You should also exclude some vegetables, especially green ones: cauliflower, cucumber, horseradish, green apples, spinach, lettuce, any greens and zucchini. Tomatoes are also excluded.
The use of iron-containing drugs, bismuth and barium sulfate is not recommended. Also, on the eve of the study, you should not take acetisalicylic acid (aspirin) and ascorbic acid (vitamin C).
Three days before the study, it is not recommended to carry out any diagnostic or therapeutic manipulations with the intestines (X-ray contrast study, sigmoidoscopy, colonoscopy).
You can not use laxatives and put enemas. Material for analysis is collected after three spontaneous bowel movements from different parts of the feces.
Menstruating women are not advised to do this test.

How to get tested correctly?

For a reliable result, after proper preparation, you need to collect the feces in a specially designed container purchased at the pharmacy. The sampling of material should be carried out after natural emptying from several areas of feces. The amount of material is sufficient in the amount of 1 teaspoon.

Interpretation of analysis results

A positive reaction of the analysis indicates processes in the intestine, leading to a violation of the integrity of its mucous membrane. This means that red blood cells and hemoglobin enter the intestinal lumen. But do not rely only on the results of one analysis. A number of diseases of the intestines and other organs can give a positive reaction. For example, nosebleeds, stomach polyps, ulcerative lesions of the esophagus, hemorrhoids and even helminths. For an accurate diagnosis, a complete examination of the patient is required.

The test result may also turn out to be false positive if there was a reaction not to human hemoglobin, but to substances or dyes contained in food. This occurs, as a rule, with incorrect or insufficient preparation of the patient for the study. In any case, a positive result is a reason for a deeper examination of the patient.

A negative test result is the norm for a person. But such a result does not always indicate the absence of intestinal bleeding and should not reassure either the patient or the doctor. A negative result has no diagnostic value. For greater reliability, if the result is negative, the analysis can be repeated three times.

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Indications

Blood in the stool can be present in people of all ages - newborn babies, nursing infants, adult men and women. The reasons for an adult and a child for which there is blood in the stool may be the same, but may also be due to age criteria.

Stomach pain is a serious symptom of trouble

In what cases is it necessary to donate feces in order to do a study for occult blood? The indications for examination are:

pain sensations in the abdomen of a constant or periodic nature;
regular feeling of nausea or vomiting;
heartburn;
chronic diarrhea or constipation;
weight loss without dietary restrictions;
the need to confirm a particular disease (ulcers, gastritis, etc.).

What do you need to know about tests?

Today, you can conduct a similar analysis yourself at home. Rapid tests are available at pharmacies. To what extent can they correctly determine the presence of blood?

It is not easy for a person who does not have special skills to comply with all the conditions, to accurately reproduce the procedure (many manipulations) when performing the test.
The test result is highly dependent on the quality of the sample.

It is easier and more reliable to carry out a fecal study in a specialized laboratory.

In laboratory conditions, three methods are used to determine blood counts in feces:

Gregersen reaction (benzidine test):
guaiac test (Weber test);
immunochemical method.

In the first method, feces are applied in a thin layer on a glass slide and dripped onto it with a reagent. The reagent contains benzidine, barium or hydrogen peroxide, acetic acid. The blood content shows a bright blue or green coloration of the test sample.

The method is simple, it allows you to detect blood at a very low concentration. But he has a significant drawback - a positive reaction can be given by eaten meat food or blood that has entered the intestines from a bleeding gum.

To obtain more reliable information, you need thorough preparation. Three days before the test, all foods containing iron are excluded from the menu, you can not drink non-steroidal anti-inflammatory drugs, laxatives.

Similarly, you need to prepare for the delivery of feces for a guaiac sample. At the slightest violation of preparation, a false positive result is possible. The quantitative side is also important - the blood loss should be at least 50 milliliters.

The essence of the method is that a small amount of feces is ground with acetic acid to a liquid porridge, then hydrogen peroxide is added and titrated with guaiac gum tincture. A chemical reaction is considered positive if a blue or violet color occurs.

The most accurate is the immunochemical method. The method is called so because the reaction is exclusively on human hemoglobin. Animal hemoglobin from food and iron from medications do not affect the result. This is an undoubted plus, since it will not cause trouble for the patient due to severe dietary restrictions and exempts from the ban on taking medications.

Colorectal cancer and polyp

What does immunochemistry show in this context? She can identify the following diseases:

polyps;
colorectal cancer;
Crohn's disease;
ulcerative colitis.

Diet

Preparing for an immunochemical test is easy. You don't need to follow a diet - you can eat everything.
With the other two methods, an iron-rich diet is required.

How to collect and donate feces correctly?

Feces should be collected only after spontaneous bowel movement. With all methods, enemas should not be done, so as not to accidentally damage the intestinal mucosa.

For the sample to be valid, no urine must enter the sample. For the same purpose, the taking of feces from a baby is not made from a diaper, but from an oilcloth.

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The essence of the analysis

Analysis of feces for occult blood shows the presence of blood particles that cannot be seen under a microscope during a coprogram. Such a study is one of the most common and allows timely detection of bleeding from the organs of the gastrointestinal tract.

Violations of the integrity of the mucosa can occur in the upper or lower part of the digestive system. In the first case, blood particles undergo biochemical processes and, getting into the feces, acquire a burgundy or brown color. If tissue damage has occurred in the area of the large intestine, the detected discharge remains scarlet.

For serious illnesses, such as malignant diseases, occult blood is the only symptom of the initial stage... Timely diagnosis makes it possible to start the correct treatment and preserve the patient's health.

When an examination is prescribed

The analysis is carried out if there is a suspicion of life-threatening diseases, or to identify the cause of pathological conditions associated with metabolic disorders. Indications for the study of feces for blood are as follows:

Helminthiasis.
Constant vomiting, heartburn, or nausea.
Stomach ulcer.
Abdominal pain of unknown origin.
Loose stools.
Excessive weight loss.
Diagnostics of the condition of the mucous organs of the gastrointestinal tract.
Digestive disorders.

In addition to all these situations, doctors prescribe a fecal examination at their discretion. It is better for the patient to agree with the doctor and conduct an additional analysis, as it will help to make the most accurate diagnosis. Thus, the response to occult blood is necessary to obtain information about the presence of damage to the walls of the digestive organs.

Types of occult blood tests

Modern research methods are more accurate and indicative than those used a few years ago. Two methods help to reveal occult blood.

Benzidine test

It was popular for a long time, as it allowed to determine even low concentrations of blood components. The principle of action is based on the identification of hemoglobin - the main component of erythrocytes. For this, a chemical reaction is used as a result of which the iron in the heme is oxidized by hydrogen peroxide and becomes blue.

The disadvantage of this method is that it is not specific. That is, a positive reaction is obtained when an iron atom of any origin, even animal and vegetable, is exposed to it. Because of this, the patient needs to undergo special training, where it is important to follow a specific diet.

Immunochemical analysis

It is a more accurate study. It is prescribed both independently and in addition to other methods to clarify their results. The principle of operation is different from the previous one. It is based on the determination of the concentration of specific antibodies that are produced in a person in response to the ingress of antigens. The method is more often used for pathologies of an infectious genesis. Of the shortcomings, the duration of implementation is noted - the final results and diagnosis become known only after 1-2 weeks.

No type of analysis suggests internal intervention or additional damage. The high sensitivity of the reagents requires some preparation of the patient in order for the results to be reliable.

Preparation for analysis

Drugs that can affect the results are canceled 1 week before the analysis.
The day before the study, it is necessary to exclude possible damage to the oral cavity, including when brushing with a hard toothbrush or eating solid food.
Women should be tested during the absence of menstruation.
A few days before taking the biomaterial, you need to follow a diet. Do not eat foods containing iron (meat, fish, tomatoes, beets). With the immunochemical method, the restrictions may not be respected.
It is not previously allowed to carry out artificial emptying with enemas and laxatives (even based on herbal ingredients).

How to collect feces correctly?

The rules for sampling biomaterial are as important as preparation for analysis. The test sample must be fresh, so the stool is delivered to the laboratory as quickly as possible.

To pass the analysis correctly, you need to be guided by the following recommendations:

Prepare a container for collecting biomaterial. It is better to use special jars that are sold in pharmacies and already contain spatulas for sampling.
After defecation, collect the dry remainder of the stool without water and urine, which accidentally can get on them. It is better to do this in the morning so that the biomaterial can be immediately taken to the laboratory.
The amount required for the study is 3 fragments of feces, which are taken from different sites. To do this, use a teaspoon or spatula from a pharmacy container.
The biomaterial must be delivered to the laboratory no later than 3 hours later... It is recommended to keep the sample in the refrigerator until this point and during transport.

Decoding analyzes

The test results are compared with the indicators that are considered the norm. Doctors allow up to 2 ml of blood to enter the intestines daily. If the number of particles detected is greater than this amount, the result is considered positive and the doctor has reason to suspect internal bleeding. When occult blood is not detected or its concentration is less than 1 mg per 1 g of feces, the test results are considered negative. Doctors only take higher values into account.

Due to improper preparation for the study, the result obtained is always erroneous. Doctors note that data distortions arise both in the direction of positive results and negative ones. In order not to doubt the obtained indicators, the study is recommended to be repeated even without any reason.

It is known that in some diseases, pathological bleeding is observed not constantly, but periodically, and this complicates its identification. If the preliminary diagnosis is known, for example, intestinal polyps, then the absence of hemoglobin will raise doubts and a second analysis will be required. That is why, to diagnose a patient, doctors prescribe several types of examinations - laboratory, instrumental.

What does a positive result say?

An increased amount of hemoglobin in feces often confirms damage to the gastrointestinal tract and the presence of pathologies. A positive analysis suggests one of the following conditions:

Crohn's disease.
Bleeding caused by varicose veins of the esophagus.
Malignant growth or polyps.
Nonspecific ulcerative colitis.
Fissure of the anus, mechanical damage due to constipation or hemorrhoids.
Oral problems.
Infection with helminths.
Ulcerative lesion of the stomach or duodenum.

Since a positive result suggests serious pathologies, the patient should make sure of the reliability of the data obtained and repeat the analysis. Small inaccuracies in nutrition or accidental damage to the oral cavity lead to false readings, and therefore it is important to properly prepare for the first examination.

The method of re-examination is chosen by the doctor - this can be a second laboratory test or an examination of the intestines using an endoscope. Often, upon receipt of confirmation of the presence of occult blood, especially by the immunochemical method, the patient is also recommended to undergo a colonoscopy.

Additional examination of the intestines will help confirm or deny the presence of bleeding polyps or other neoplasms. The feasibility of the double screening algorithm has been proven in screening programs. Thanks to this approach, patient mortality was reduced by 25%.

The interpretation of the results is carried out only by a doctor, who takes into account the permissible norms, the patient's history, the clinical picture, and the indicators of other examinations. It is impossible to independently interpret the obtained data or try to correct them with drugs.

Doctor's conclusion

Only comprehensive diagnostics will make it possible to establish the exact cause of the pathology and decide on the necessary therapy. A detailed study of feces, including occult blood, is recommended to be carried out annually for preventive purposes. Moreover, it must be done 2-3 times or combined with other techniques.