Contents
- Faecal occult blood test – how is the test performed?
- Fecal occult blood test – why is it worth doing a fecal occult blood test?
- Faecal occult blood test – who should perform a faecal test and how often?
- Fecal occult blood test – how to prepare for the test?
- Faecal occult blood test – sampling
- Faecal occult blood testing – what is the purpose of the test?
- Faecal occult blood test – how to interpret the results of the faecal test?
- Faecal occult blood test – is there anything else you should know?
- Is the home test for fecal occult blood as effective as laboratory methods?
- Tests your doctor may recommend if the test is positive
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The fecal occult blood test is a non-invasive test that detects the presence of blood in the stool that is not macroscopically (with the naked eye) visible. Blood can come from any part of the digestive tract. Blood in the stool is one of the most common warning signs of cancer in the colon.
Minimal amounts of blood are excreted from the intestinal lumen together with the faeces each day. However, they are so small that no test can detect them. A positive occult blood test (FOBT) therefore indicates increased (non-physiological) blood loss through the gastrointestinal tract.
Faecal occult blood test – how is the test performed?
There are two types of tests:
1) traditional guaiacol – gFOBT, and 2) tissue test (newer).
The difference between them mainly boils down to the method of conducting this study. The tissue test is available over the counter in pharmacies. The guaiacol test, on the other hand, is performed in a laboratory and analyzed by specialists.
At Medonet Market you can buy a Home Fecal Occult Blood Test – FOB TEST. You can buy it separately or in a home test kit for stomach problems.
Fecal occult blood test – why is it worth doing a fecal occult blood test?
Occult blood tests are able to detect even small amounts of blood from the gastrointestinal tract. A common cause of such bleeding is colon cancer.
Faecal occult blood test – who should perform a faecal test and how often?
In healthy people of both sexes, with no family history of colorectal cancer, after the age of 50, it is recommended to perform occult blood testing once a year.
You can purchase a faecal occult blood test cassette for home testing from the Medonet Market. In the set of tests for stomach problems – home cassette tests you will buy a fecal occult blood test together with a test for Helicobacter Pylori.
Fecal occult blood test – how to prepare for the test?
Your doctor may ask you to avoid taking certain medications or follow an adequate diet for the several days leading up to a faecal occult blood test. It is also worth remembering not to undergo any dental procedures for a few (approx. 3) days before sampling. As a result of bleeding from the gums (during the procedure or due to gum disease), blood may enter the digestive system – then the test will give a positive result (in this case – a false positive). It is worth bearing in mind that taking aspirin increases the risk of bleeding from the gastric mucosa, and thus – a positive result in the occult blood test. Therefore, unless your doctor tells you otherwise, you should stop taking aspirin 3 days before submitting your stool samples for testing.
Ingredients in certain foods, such as red meat, broccoli, turnips, and horseradish, and some medications, such as colchicine, iodine, and boric acid, may react with the dyes on the applicator of the test, resulting in a false-positive result. On the other hand, vitamin C interferes with the operation of the test and this test – even in the presence of blood in the collected sample – will give a false negative result.
Due to the above-mentioned effects, ask your doctor to provide you with a list of foods and medications that should be avoided in the period leading up to a faecal occult blood test.
Faecal occult blood test – sampling
For the gFOBT test, you will receive at least one test paper from your doctor or lab representative. Samples should be taken from 3 consecutive bowel movements – usually within 3 consecutive days. Each sample should be placed in a separate clean container. Avoid contamination with urine or water. Your name and the date you collected the material are always shown on the test paper. Using the applicator, take a small stool sample and transfer it to the place marked on the test paper, and then wait a moment for the specimen to dry. Depending on the test subtype, all three samples should be on one or three separate test papers. Ask your doctor or the person who will give you a faecal occult blood test for details. After collecting the samples, they should be returned to the laboratory or other place indicated by a doctor.
When it comes to over-the-counter tests available in pharmacies, the applicator is placed in the toilet immediately after defecation. The test contains chemicals that will discolor the applicator when blood is present in the stool. Keep in mind that this method is more subjective than a laboratory test. As with the gFOBT test, it should be repeated for 3 consecutive days.
Faecal occult blood testing – what is the purpose of the test?
Stool occult blood testing is primarily used as colorectal cancer detection method. Blood in your stools may be the only symptom of an ongoing cancer. And the sooner cancer is found, the more likely it is to cure it.
FOBT is also useful in determining the causes of anemia, for example if it is caused by bleeding from a gastric ulcer. Therefore, if you develop symptoms of anemia such as fatigue, fast heart rate at rest, palpitations, and your blood test shows low hemoglobin and hematocrit levels, your doctor may order you to perform a blood occult blood test.
Faecal occult blood test – how to interpret the results of the faecal test?
The correct FOBT test result is negative (no blood in the stools). On the other hand, a positive test result indicates the presence of blood in the stool – due to gastrointestinal bleeding (bleeding ulcer, intestinal recesses, polyps, inflammatory bowel diseases, hemorrhoids, cancer) or blood ingestion (bleeding from the nose, gums).
Faecal occult blood test – is there anything else you should know?
Bleeding from polyps or neoplastic tumors is periodic. So blood does not appear every time you have a bowel movement. Hence, taking 3 samples over the next 3 days increases the chances of detecting any existing bleeding.
Is the home test for fecal occult blood as effective as laboratory methods?
Although home tests based on the change in the color of the applicator due to contact with the sample are highly sensitive tests, your doctor may recommend that you perform a stool laboratory analysis (gFOBT).
Read more: Home Tests – Before Visiting Your Doctor
Tests your doctor may recommend if the test is positive
- Sigmoidoscopy. Examination of the lower part of the large intestine, during which an endoscope with an optical fiber and a camera is inserted into its lumen in order to visualize any abnormalities, e.g. polyps.
- Colonoscopy. The examination is a more detailed examination than sigmoidoscopy – based on the same principle, but covering the entire colon.
- Double contrast study. A series of X-ray pictures of the abdominal cavity taken while passing through the intestines of the previously administered contrast agent.
Are there other types of tests that can detect colorectal cancer early on in a stool test?
Yes. A test for the presence of cancer cells in stools is available on the market. Previous scientific studies have confirmed the high sensitivity of this method – although it does not allow the detection of all types of colorectal cancer.