But hidden blood can indicate no less formidable diagnoses, and when the disease is still at an early stage of development, and the chances of a successful recovery are much greater. That is why, in the presence of the first suspicious symptoms, it is necessary to obtain qualified medical advice and pass all the necessary tests. And people over the age of 50 with a history of colorectal cancer should have a fecal occult blood test every year, as this simple measure can save lives in some cases.
Many pathologies of the gastrointestinal tract, including ulcerative colitis and malignant tumors of the intestine, for the time being do not bother the patient with severe discomfort. But the destruction of healthy tissues is already taking place, therefore, blood is released, which cannot yet be visually detected in the feces, but it is quite possible to do this with the help of special laboratory samples. Today we will tell you what a fecal occult blood test shows, how to prepare for the study and what diet you need to follow, how to collect and donate material correctly, what a positive and negative result indicates, in which cases it can be false, and what methods of determining occult blood in the feces are most accurate.
Hidden blood in stool - what does it mean?
A certain amount of blood can normally be present in the feces - no more than 2 mg of hemoglobin per 1 g of feces, at such a maximum concentration it turns out that a healthy person loses up to 2 ml of blood with feces per day. If the bleeding becomes more intense, the color of the feces changes, and its shade indicates the localization of the problem: the darker, the higher. For example, with a bleeding ulcer of the stomach or duodenum, the feces become black, tarry (melena), if the cause lies in an exacerbated ulcer, the stool will become burgundy, and bleeding polyps, hemorrhoids and malignant neoplasms in the rectum lead to the appearance of scarlet streaks and spots on stool masses. Such signs cannot go unnoticed and should be the reason for immediate medical attention.
Occult blood in the stool is blood that cannot be detected either by visual or microscopic examination of stools. Only a fecal occult blood test allows you to find it - a positive result indicates the presence of occult gastrointestinal bleeding and requires a mandatory additional examination of the patient.
Who needs a fecal occult blood test?
This kind of research is assigned in the following cases:
Persistent periodic pain in any part of the abdomen, as well as in the right or left hypochondrium;
Discomfort and soreness during or after a bowel movement;
Sensation of the presence of a foreign body in the rectum;
Loss of appetite, a sharp decrease in body weight for no apparent reason;
Nausea, vomiting, belching, heartburn, bad taste in the mouth;
Diagnosed pathologies of the gastrointestinal tract: Crohn's disease, intestinal polyposis, diverticulosis, esophageal varicose veins, helminthiasis, and so on - the study is performed to determine the stage of the disease or control the course of treatment;
Alarming results from other previous examinations, such as a general or biochemical blood test;
Prevention of bowel cancer over the age of 40-50 years in patients with unfavorable heredity.
Preparation, diet, collection and delivery of analysis
It makes sense to conduct a study on occult blood in the feces only if the rules of preliminary preparation are carefully observed, otherwise the probability of obtaining a false result will be very high.
Let's start in order:
Temporarily postpone analysis it is necessary until the following circumstances are eliminated - periodontal disease, epistaxis, menstruation, hematuria, exacerbation of hemorrhoids, recent diagnostic manipulation with the intestines (colonoscopy, sigmoidoscopy), anal sex. All these factors are likely to lead to a distortion of the results of the study, which means that it is necessary to solve the existing problem or wait a few days, depending on the situation;
One week before analysis you should refuse to take any medications that undesirably affect the composition of feces, namely, NSAIDs (aspirin, ibuprofen, naproxen), barbiturates, anticoagulants, intestinal motility stimulants, ascorbic acid, drugs and dietary supplements containing iron. If you are constantly taking any medications, and you are not sure that they will not affect the results of the study, it is better to consult your doctor in advance;
Three days before analysis you need to start dieting - a fecal occult blood test is almost always carried out using laboratory samples that are sensitive to the composition of the food consumed by the patient. Therefore, you will have to temporarily give up any meat, poultry, fish and offal - that is, everything that may not contain your blood. In addition, it is recommended to exclude from the menu some beans, vegetables, fruits and berries that are rich in iron and vitamin C or strongly affect intestinal motility - for example, apples, celery, cranberries, oranges, spinach, nuts, cabbage, tomatoes, carrots, beets, beans, soybeans and lentils;
12 hours before analysis it is necessary to put down the toothbrush and stop eating hard foods that can injure the gums and lead to blood from the mouth into the digestive tract.
Successful occult blood test = preparation + diet, remember this!
So, preparatory stage behind, it is time to collect material for research and take it to the laboratory:
Early in the morning, before breakfast, make an external toilet of the intimate area using ordinary soap, rinse thoroughly and dry;
Defecate in a pre-prepared clean container. The process should occur naturally, without the use of enemas or laxatives. You can't take a stool sample from the toilet. An analysis of feces for occult blood in a child is taken from a well-washed pot, from a diaper or oilcloth;
For the collection and transportation of biomaterial, special sterile containers with a lid and a spoon, which are sold in any pharmacy, are best suited. In the absence of such, you can use a small glass jar, having previously disinfected it. Collect a little feces from different parts of the stool so that the picture of the study is as objective as possible. In total, an amount approximately equal to 2-3 teaspoons is enough;
It is better to deliver the container with the sample to the laboratory immediately. However, storage of the material in the refrigerator for no more than 12 hours is acceptable. This is especially helpful with young children whose stools are unpredictable, or people who are used to having a bowel movement before bed.
Research methods: pros and cons
Currently, four main methods for determining occult blood in stools are used:
Gregersen reaction (benzidine test);
Weber reaction (guaiac test);
Let's look at the essence of these methods, their advantages and disadvantages. Looking ahead, we note that in Russia the most commonly used benzidine test and immunochemical analysis, but are they the most accurate?
Gregersen reaction (benzidine test)
The benzidine test is a simple and quick laboratory test that allows you to detect blood not only in the feces, but also, for example, in urine, vomit and any other body fluid of the patient. This is possible due to the oxidation of benzidine (paradiaminodiphenyl) with hydrogen peroxide or barium in the presence of hemoglobin. The benzidine test has several variations, the most commonly used of them was proposed by the doctor M. Gregersen, and therefore bears his name.
The essence of the method is as follows: take 0.025 g of benzidine, add 0.1 g of barium peroxide and 5 ml of 50% acetic acid solution to it, shake everything until completely dissolved, put a few drops of the composition on a glass slide, on which the test feces are smeared with a thin layer, and watch the reaction. If there is occult blood, a bright blue-green coloration occurs. Exists Alternative option- prepare a saturated solution of benzidine in acetic acid and mix with a 3% solution of hydrogen peroxide in equal parts. The result will look about the same, and the cost of the study will change little.
Pros:
Very high sensitivity - 1:100,000;
The speed of obtaining the result - almost instantly;
Availability in any laboratory;
Low price.
Minuses:
The need for careful preparation for the delivery of a fecal occult blood test using the Gregersen method, since the benzidine test gives a positive reaction to animal hemoglobin from food.
Weber reaction (guaiac test)
In addition to the two voiced, this diagnostic method has several more names: the Van Deen or Almen-Van Deen test, the hemoccult test. Curiously, the reaction using guaiac resin is the first method in world medical practice for detecting occult blood in feces and other human biological fluids. Dr. Van Deen proposed it in 1864, and it is still actively used in many countries.
The essence of the guaiac test is as follows: they take 3-5 g of the test feces, dissolve it in acetic acid, and an ethereal extract is released, hydrogen peroxide and tincture of guaiac resin are added to it, and then the color change of the reagents in the test tube is observed. If the composition turns blue, then the test result for occult blood in the feces is positive. The test is repeated a total of six times: two samples are studied from biomaterials taken consecutively within three days.
Pros:
Efficiency.
Affordable price.
Minuses:
Low sensitivity - the reaction will be positive only in case of blood loss in the amount of 30 ml or more, colorectal cancer is found in a third of cases, benign intestinal tumors - only in 15% of cases;
Strict dietary requirements before testing feces for occult blood - guaiac test is sensitive not only to human hemoglobin heme peroxidase, but also to peroxidases of other hemes contained in food.
This analysis is otherwise called an immunological or immunochromatographic test. The technique is based on the reaction that occurs when specific antibodies interact with human blood hemoglobin. Errors are excluded because the antibodies do not react to animal hemoglobin or the iron found in some plant foods. Immunochemical analysis of feces for occult blood appeared in the arsenal of physicians relatively recently and has already firmly established itself there.
The essence of the technique is as follows: a sample of the studied feces is applied to a test strip or placed in a tablet window with reagents - monoclonal antibodies. If human hemoglobin is present in the biomaterial, it binds to antibodies, and a bright pink or purple band appears in the control area. The second band appears in any case - it is an indicator of the quality of the device. Taking a fecal occult blood test using this method is very similar to taking a pregnancy test - everything is very simple, fast and understandable.
In a pharmacy, you can purchase "ImmunoCHROME-GEM-Express" or any other similar device for self-diagnosis of hidden gastrointestinal bleeding at home, however, to obtain a reliable result, it is recommended to conduct an analysis at least three times with intervals of several days.
Pros:
Speed and convenience;
No need for preliminary preparation and diet;
High accuracy - determines the early stages of colorectal cancer in 97% of cases.
Minuses:
Relatively high cost;
Availability not in every laboratory;
The objectivity of the results of the analysis of feces for occult blood only in the case of bleeding in the lower parts of the digestive tract. Aggressive enzymes that act on hemoglobin in the stomach and small intestine make it unsuitable for reaction with monoclonal antibodies.
To complete the picture, it should be mentioned that occult blood can be detected in stool during chemical reaction using destructive agents. Nitrogen-containing pigments, porphyrins, contained in hemoglobin molecules and released outside when they die, have an ultra-high light absorption coefficient - about 10 to the 6th degree. Their bright fluorescent glow is recorded by the laboratory assistant in the event that there is occult blood in the studied stool sample. However, in Russia this diagnostic method is not very popular, especially in comparison with the benzidine test.
Pros:
Efficiency;
Affordable price;
Relatively high accuracy - about 80%.
Minuses:
The need to follow a diet, since porphyrins are present in any hemoglobin, including in an animal.
Deciphering the results of an occult blood test
Depending on how the test was carried out and what the internal regulations of the laboratory are, you will receive an answer in 1-6 days. From the description of the methods for conducting this study, it can be seen that its results cannot be expressed in an exact digital equivalent: in the benzidine and guaiac samples, the reagent is either stained or not - only the speed and intensity of the color differ. As for the enzyme-linked immunosorbent and fluorescent test, everything is also clear here: the second strip either appears or not, and the glow is either there or not.
For example, consider the decoding of the results of the analysis of feces for occult blood according to the Gregersen method (benzidine test):
Important: even a weak reaction usually alarms the doctor and prompts him to repeat the test or add additional diagnostic methods to it, since the presence of latent blood in the feces is a sign of serious trouble.
Let us now consider why the results of the study may turn out to be biased:
False negative fecal occult blood test result- this is almost always a consequence of a violation of the technology of conducting a sample or poor quality reagents. It may also be that the patient provided little biomaterial or was too lazy to collect it from different fragments of feces. In addition, in some diseases of the gastrointestinal tract, for example, with polyposis of the large intestine, neoplasms bleed not constantly, but episodically. Therefore, the study is recommended to be repeated several times, especially if there are serious reasons to suspect the disease;
False positive occult blood test result- this, in most cases, is a consequence of neglecting the rules of preparation. Either the patient did not follow the diet prescribed by the doctor, or took any medications that distorted the picture of the study, or allowed an injury that led to blood entering the gastrointestinal tract. In infants, a positive fecal occult blood test result can be false if the nipples of a nursing mother are cracked and bleeding - then the baby swallows blood during feeding, and it ends up in his stool. Moreover, this problem cannot be solved by pumping, the blood in this case can also get into breast milk. It is better to transfer the baby to an artificial mixture for three days in order to be sure of the objectivity of the test.
Positive result - what to do?
Anxious patients are primarily concerned with the question: what does a positive fecal occult blood test result mean? First of all, this is definitely not a reason to panic. We have already discussed the rather high probability of errors, especially when preconditioning rules are violated. It is imperative to repeat the study at least three times before drawing final conclusions.
Secondly, even if a positive result turned out to be reliable, it most likely signals the most common diagnoses:
If symptoms occur, the doctor must confirm the diagnosis with the help of objective studies before prescribing treatment. First of all, laboratory tests are carried out that can show a deviation from the norm.
The patient is prescribed general analysis blood, feces, urine. If a specialist has a suspicion that a pathology of the gastrointestinal tract is developing, leading to internal bleeding, then a test is prescribed in order to detect it.
Why is a fecal occult blood test done?
With pathology of the mucous membrane of the esophagus, stomach, duodenum, feces become almost black or dark red due to contact of blood with enzymes. If the integrity of the intestines is broken, then the feces acquire a bright red color. With significant bleeding, the patient needs emergency medical care.
Bleeding is not always constant, ulcers and inflammations bleed periodically. With a small involvement of blood vessels in the pathological process, the shade of feces and their consistency does not change.
If no blood is detected during the coprogram, and the doctor suspects occult bleeding, then the patient should take another test. The reaction to occult blood in the feces is positive, while bleeding is not necessarily present, that is, the result is false positive.
When to take the test
- abdominal pain that is constant or occurs intermittently;
- nausea and vomiting;
- heartburn;
- emptying in consistency differs from the norm (mushy);
- false urge to defecate;
- frequent constipation;
- diarrhea;
- weight loss, lack of appetite;
- hyperthermia.
If the bleeding is not severe, then it is impossible to notice blood in the feces without special reagents
The study allows you to confirm the diagnosis. It is also carried out if the patient has been diagnosed with gastrointestinal diseases using other diagnostic methods. The results will help the specialist understand the degree of mucosal damage and determine the severity of the disease, and a repeat test will show how effective the prescribed therapy is.
How to take an analysis
A therapist, oncologist, surgeon, gastroenterologist can prescribe a test. Prior preparation is required before delivery. Doctors give the following recommendations. 72 hours before the test, exclude iron-containing foods from the menu, as well as tomatoes and vegetables and fruits that have green color. You should not eat meat or fish, because they contain hemoglobin.
For a week, stop taking medications such as aspirin, laxatives, iron tablets, non-steroidal anti-inflammatory drugs. If it is not possible to stop drug therapy, then the doctor should be informed about the drugs taken.
Do not eat foods that change the color of feces. The collection of material should be carried out before diagnostic manipulations in the digestive tract. It is not recommended to do an enema or take laxatives to speed up the collection of a sample for analysis.
Do not collect a sample during menstruation. If X-ray diagnostics was carried out, then the analysis can be taken only after 2-3 days.
If the subject has periodontal disease, in which there is severe bleeding of the gums, then one day before collecting feces, it is not advised to brush your teeth, since the blood that has entered the stomach can give a positive result.
You need to take the material from three different sides of the stool. An unreliable answer is likely if water or urine enters the sample. In order to exclude this, it is recommended to lay an oilcloth on the toilet. The test sample must be placed in a plastic container (available at a pharmacy) and brought to the laboratory within the next 2-3 hours.
What does it mean if the result is positive?
An occult blood test is positive if a pathology develops in which a certain amount of blood enters the lumen of the stomach or intestine. That is, there is a disease, which is characterized by inflammation of the mucosa and its perforation.
In some cases, the tumor is manifested only by the release of a small amount of blood in the feces.
In young children, blood may also be seen in the stool. Quite often this is due to the child's intolerance to cow's milk. If the baby is breastfed, then even the use of milk, butter, sour cream by the mother can cause bleeding.
If the child has lactose intolerance, then you need to carefully select an artificial mixture.
Bleeding in a baby can be caused by dysbacteriosis, amoebiasis, colitis, dysentery. One of the reasons for the presence of blood in the feces is the cracks in the anus, resulting from the passage of too hard feces. This happens if the child does not drink enough fluids.
Slightly, but constantly bleeding from the moment of formation. If the bleeding has become profuse, then it will be detected during the coprogram. An occult blood test helps to see the symptoms of cancer in early period and this increases the chances favorable outcome illness. A positive test for occult blood will be due to bleeding from the nose or gums, pharynx.
How is the presence of blood in the stool determined?
During the study, apply chemical substances, which, upon contact with an erythrocyte, change color under the action of oxidation. The Gregersen method allows you to see even a small amount of hemoglobin. Benzidine stains iron Blue colour.
Taking into account the speed of staining and its intensity, a weakly positive (+), positive (++ or +++) and sharply positive (++++) reaction is established. When using benzidine, it is possible to establish blood loss of more than 15 ml / day, which often gives false positive results.
Immunochemical analysis of feces is considered more accurate. It uses antibodies to human hemoglobin, so there is no need to diet. The test is highly sensitive, it will detect 0.05 mg of hemoglobin per gram of stool (at 0.2 ml/g of feces, the test is considered positive).
This method allows you to detect tumor formations in the large intestine, but does not detect bleeding from the esophagus or stomach. In 3% of cases, tests give a positive result in the absence of a neoplasm in the large intestine.
Reasons for false positive and false negative results
Normally, there is no blood in the feces, so if there is no pathology that provokes bleeding in the esophagus, stomach or intestines, then the result of the analysis will be negative. Under some circumstances, a fecal occult blood test will give a false positive or false negative result.
So, often the study does not detect blood in case of formation in the large intestine, therefore, colonoscopy or flexible sigmoidoscopy is used to confirm colorectal cancer and polyps.
A false-positive result can be obtained if there was no preparation for the study, if there is bleeding gums, or if the patient has frequent nosebleeds. There will be blood in the stool if the mucous membrane is injured, for example, the patient cuts the esophagus with a fish bone.
As a rule, the analysis gives a false positive result if the patient ignored the doctor's recommendations and did not adhere to the diet.
More often, an analysis is carried out specifically for the presence of iron in the feces, so even an apple eaten yesterday can stain the sample, which will be interpreted as the presence of blood. To exclude false-positive or false-negative results, it is recommended to carry out diagnostics three times (samples of three consecutive bowel movements) and follow all recommendations for preparing for the study and collecting material.
If the analyzes show twice a large number of hemoglobin in feces, they are considered reliable.
If the analysis turned out to be uninformative, then the doctor prescribes a hardware study - a colonoscopy. It consists in examining the surface of the large intestine with an endoscope inserted through the anus.
Such a diagnosis will allow you to see the exact localization of the lumen. To determine the condition of the lining of the esophagus or stomach, endoscopy is used, in which a flexible tube is inserted through the mouth. In order to exclude an erroneous result, it is recommended to take the analysis three times.
If the study gave a negative result, then the doctor will not exclude a peptic ulcer or a cancerous lesion of the organ of the digestive system. Based on the analysis of fecal occult blood alone, a diagnosis cannot be made, it only means that a pathology is present and, together with the clinical manifestations of the disease, allows a preliminary diagnosis to be made.
When a person is spoken of as secretive, this characteristic often takes on a negative formulation. But is it that bad secretive person how do they think about it?
In fact, secrecy is not the worst character trait. Read about its advantages and disadvantages below.
Definition
Secrecy is the unwillingness to share one's thoughts, feelings, emotions with others. The ability to experience everything in yourself. If the individual is secretive, this is a real treasure, on the one hand. After all, words cannot be pulled out of him with ticks. With this, it’s not scary to go into reconnaissance.
Only such a person has a very difficult time. Why? Now let's deal with this issue.
Advantages of Stealth
Secretive is a person who knows how to keep a face. A storm breaks out in his soul, but he looks absolutely calm. And not a single muscle trembles on the face.
The main advantages of this character trait:
- These people can be trusted with everything. And to be sure - they will not give up.
- A secretive friend will never complain about how bad his life is.
- In any, even an extraordinary situation, a person maintains a steely endurance.
- As a rule, secretive people are smart and perceptive. They don't waste themselves on the outside, they focus on the inside.
Disadvantages of Stealth
On the one hand, this is a very good feature. But on the other hand, its owners have a very hard time:
- Such a person does not know how to merge emotions. He accumulates all the negativity in himself, unable to throw it out.
- Reticence is often intertwined with shyness. These people are afraid to say something once again. They live in their "shell".
- Due to the lack of emotions, others do not understand what a person is experiencing.
- It is difficult to communicate with such a person. It looks like an impenetrable wall, behind which it is not known what lies.
Good or bad?
Summing up, let's ask a question. Stealth - is it good or is it bad? Everything depends on the situation. Sometimes it is extremely necessary to be able to keep a face and remain silent. And sometimes more vivid emotions are required than cold equanimity.
Each quality has its own advantages and disadvantages. We talked about the advantages and disadvantages of secrecy above.
Conclusion
That's what secrecy is. And a secretive comrade is a special type of person. Pick up the keys to it must be carefully. And most importantly - when choosing, do not break the keyhole.
In fact, secrecy is neither good nor bad. It's just a character trait that some people have. Someone has an excessive emotionality that frightens others. And others are too restrained, which can also cause bewilderment.
Guys, we put our soul into the site. Thanks for that
for discovering this beauty. Thanks for the inspiration and goosebumps.
Join us at Facebook And In contact with
There are many ways to read not even a person’s thoughts, but his thoughts, his deepest hopes and fears. Everyone can develop the ability to see through people: it is enough to know about a few points in the behavior of the interlocutor that you should pay attention to. Practice "reading people" more often, get yourself into this habit, and after a while you will be impossible to deceive.
All people are different and everyone has their own habits and characteristics. Somebody
sorting through objects on the table, someone wrinkles his nose funny, shakes his legs,
touches the chin. These behaviors can indicate nervousness, distrust, and more. Or they may be a habit of this person that has nothing to do with what is happening.
That's why it is important to determine which behaviors are the norm for a particular person. And then pay attention to any deviations from the norm, to minor changes in the behavior and facial expressions of the interlocutor. They are the very essence.
Watch from the sidelines and compare
To complete the picture, it is useful to observe the interlocutor from the side: how he
behaves before communicating with you, how it communicates with other people, what language says
his body. During a conversation with you, he will behave a little differently, he will
try to impress. By comparing what you see, you will get much
more information about the person. After the meeting, do not rush to leave either - see if his mood and behavior have changed.
Always adjust for context
All people in society unconsciously play roles and adjust a little to each other, mirroring the gestures of people they like or those they want to impress. Make allowance for the context in which the person you are trying to read is located, because in different circles there may be different rules. For example, in some countries, eyes are averted because it is customary to express respect, and not at all because of a sense of embarrassment.
Wrinkles reflect the character of a person. If a person frowns and twists his mouth for years, it will be noticeable. Facial expressions can tell a lot.
- When a person longs to be understood and convincing, he raises his eyebrows, wrinkling his forehead. People who have pronounced longitudinal wrinkles on their foreheads have been trying all their lives to establish contact with others and want to be heard.
- When you are attractive to the interlocutor, his facial muscles relax, his head tilts a little to one side, blood rushes to his lips, making them a little plump and brighter. If meeting with you is unpleasant for him, his face will be slightly tense.
- If you see a smile on a person’s face, but there are no wrinkles in the corners of his eyes, then he smiles at you insincerely - this is a fake smile. Such a smile can also indicate that the interlocutor feels uncomfortable.
- Squinted eyes during a conversation (as if a person is trying to see something small) indicate that he is trying to understand, understand, concentrate, and probably feels out of his element. If a person with a squint looks directly into your eyes, then this signals his distrust and ill will.
- Dilated pupils speak of strong sensations, of sympathy, excitement, interest. When a person quickly sorts through thoughts in his head, frantically looking for a solution, his eyes run around.
- If a person avoids direct eye contact or, on the contrary, looks too closely into your eyes, there is a high probability that he is telling a lie.
Most often, when a person remembers something, his pupils are directed either up or to the left and up. But when writing and inventing on the go, a person looks to the right and up.
Behavior in a team
In collectives, people are grouped according to the similarity of views or characters. Observe your interlocutor, find out with whom he prefers to spend time. A lot will also be said about how he behaves with people, whether he is worried about the convenience of others or unceremoniously interferes with them and does not even notice it.
- A talkative and verbose person is usually proud and touchy.
- Quiet speech and avoidance of public statements are inherent in people prone to self-criticism, assiduous and insecure.
- If the interlocutor constantly interrupts, hears only himself - he is pessimistic, distrustful and selfish.
- If a person speaks little, this does not always indicate his stiffness. Perhaps this is a sign of success: such people talk less and do more.
We feel that he should not be trusted: having sufficient experience in observing people, we subconsciously and very quickly compare the smallest details of behavior and recreate a complete picture. This is how intuition works. It can and should be developed, and it should also be listened to more often. Of course, sometimes we can make mistakes in our intuitive assessments, but gradually, with practice and experience, we will make fewer and fewer such mistakes.
Can a person hide their true intentions feelings and fears? Or, knowing the intricacies of behavior, facial expressions and gestures, you can figure out absolutely any person, even the biggest cunning and skillful actor? How do you think?
