A heme occult test is a diagnostic tool used to detect blood in the stool. It is also known as a fecal occult blood test (FOBT). The test is important in identifying gastrointestinal bleeding, which may indicate underlying health conditions such as colorectal cancer, gastric cancer, or digestive system disorders. The heme occult test works by detecting the presence of heme, a component of hemoglobin that gives blood its red color. In the test, a small sample of stool is collected, usually by the patient using a kit provided by a healthcare professional. The sample is then analyzed for the presence of heme using a chemical reaction, which can determine if there is blood present.
Begin with all of your supplies ready and in one place. Supplies will include a test kit, test cards, either a brush or wooden applicator and a mailing envelope. The kit will give you detailed instructions on how to collect the stool. The instructions below can be used as a guide, but your kit instructions could be a little different, so always follow those instructions first.
Ulcers, hemorrhoids, diverticulosis tiny pouches that form at weak spots in the colon wall or inflammatory bowel disease colitis may also cause blood in your stool. Place the test kit in the mailing pouch provided and return it to your doctor or lab as soon as possible but within 14 days of taking the first sample.
The sample is then analyzed for the presence of heme using a chemical reaction, which can determine if there is blood present. There are two methods commonly used for the heme occult test: the guaiac-based method and the immunochemical method. The guaiac-based method involves applying a chemical solution called guaiac to the stool sample.
There are many choices for early detection
This test can detect small amounts of blood in stool. It requires abstaining from red meat and certain medications for a number of days before. An FOBT is more specific to finding blood from further up the digestive tract, such as the stomach.
- Looks for blood in stool
- Doctor may ask you to avoid certain foods and medicines
- No risk involved
- Inexpensive and generally covered by insurance
Advantages
- Inexpensive; covered by most insurance
- Can be simple to complete
- Can be completed in the comfort of your own home
Disadvantages
- Cannot identify polyps; can only detect signs of cancer
- Will need a colonoscopy if test is positive
- Patients may find test unpleasant
- Requires strict adherence to the test protocol for the test to be accurate (restricted diet and multiple days of stool collection)
- High false positive rate — non-cancerous conditions may also cause blood in the stool and not specific for human blood
- May miss tumors that bleed in small amounts or not at all
What can I expect for a bill?
Average cost before insurance: about $5
Will my insurance cover it?
Medicare covers FOBT once a year for individuals 45 and over. Most other insurances cover the test too; talk to your carrier.
The facts
The guaiac fecal occult blood test (FOBT) is used to find occult blood (or blood that can’t be seen with the naked eye) in stool. The idea behind this test is that blood vessels at the surface of larger polyps or cancers are often fragile and easily damaged by passing stool. The damaged blood vessels usually release a small amount of blood into the stool, but only rarely is there enough bleeding to be visible in the stool. The FOBT is an easy way to determine whether there is blood in your stool, which could be the result of polyps or colorectal cancer.
So how does it work? The FOBT detects blood in the stool through a chemical reaction. However, it can’t tell if the blood is from the colon, rectum, or from other parts of the digestive tract, like the stomach. If this test is positive, a colonoscopy will be needed to find the reason for the presence of blood. Although cancers and polyps can cause blood in the stool, there are other causes too. Ulcers, hemorrhoids, diverticulosis (tiny pouches that form at weak spots in the colon wall) or inflammatory bowel disease (colitis) may also cause blood in your stool.
This screening test is done with a kit that you can use in the privacy of your own home. Another important part of this kit and test is that it requires you to check more than one stool sample. Also, unlike some other screening tests (including colonoscopy), this one must be repeated every year.
The prep
Some foods or drugs can affect the outcome of the FOBT, so your doctor may suggest that you avoid the following before this test:
- Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil), naproxen (Aleve) or aspirin (more than one adult aspirin per day), for seven days before testing
- Vitamin C in excess of 250 mg daily from either supplements or citrus fruits and juices for three days before testing
- Red meats for three days before testing, as the components of blood in the meat may cause the test to show positive
The procedure
Begin with all of your supplies ready and in one place. Supplies will include a test kit, test cards, either a brush or wooden applicator and a mailing envelope. The kit will give you detailed instructions on how to collect the stool. The instructions below can be used as a guide, but your kit instructions could be a little different, so always follow those instructions first.
First, you’ll need to collect a sample from your bowel movement. You can place a sheet of plastic wrap or paper loosely across the toilet bowl to catch the stool or you can use a dry container to collect the stool – whichever you prefer. Make sure the stool specimen does not mix with urine. After you obtain a sample, flush the remaining stool down the toilet.
Use a wooden applicator or a brush to smear a thin film of the stool sample onto one of the slots in the test card or slide.
Next, collect a specimen from a different area of the same stool and smear a thin film of the sample onto the other slot in the test card or slide.
Close the slots and put your name and the date on the test kit. Store the kit overnight in a paper envelope so it can dry.
Repeat the test on your next two bowel movements, if instructed. Most tests require collecting more than one sample from different bowel movements to improve the accuracy of the test. Because many cancers don’t bleed all of the time, blood may not be present in all stool samples.
Place the test kit in the mailing pouch provided and return it to your doctor or lab as soon as possible (but within 14 days of taking the first sample).
The big 'what if…'
For the FOBT, a positive test result indicates that abnormal bleeding is occurring somewhere in the digestive tract. As we’ve stated, this blood loss could be due to a number of things besides cancer, so if the test finds blood, a colonoscopy will be needed to look for the source.
How often (if not high risk)
Once a year starting at age 45.
You can reduce your bowel cancer risk by:
If heme is present, the guaiac reacts with it, causing a blue color change. The immunochemical method uses antibodies specific for human heme, which produce a color change or trigger a reaction when heme is present. It is important to note that a positive heme occult test does not necessarily mean that there is a serious health condition present. There are various reasons why blood may be present in the stool, such as hemorrhoids, gastrointestinal ulcers, or inflammation. However, further diagnostic tests will be required to determine the underlying cause of the bleeding. Routine screening with a heme occult test is often recommended for individuals over the age of 50, as they are at a higher risk for developing colorectal cancer. The test is also used in individuals with symptoms such as unexplained anemia, changes in bowel habits, or abdominal pain. Overall, the heme occult test is a valuable tool in diagnosing gastrointestinal bleeding and detecting potential health issues. It is a simple and non-invasive test that can provide important information about a person's digestive health. If you have any concerns or symptoms related to gastrointestinal bleeding, it is recommended to consult with a healthcare professional who can determine whether a heme occult test is appropriate for you..
Reviews for "Heme Occult Test: Potential Applications in Veterinary Medicine"
- John - 2 stars - I did not like the Heme Occult Test at all. The instructions were unclear and I could not understand what I was supposed to do. Additionally, the test itself was messy and difficult to use. Overall, I found it to be a frustrating experience and would not recommend it.
- Sarah - 1 star - I was highly disappointed with the Heme Occult Test. The results were inaccurate and inconsistent. I followed the instructions carefully, but still got different results each time I took the test. It was a waste of time and money. I would not trust this test for detecting occult blood.
- Michael - 2 stars - The Heme Occult Test was a complete letdown. I found it to be overly complicated and time-consuming. The test strips were flimsy and difficult to handle. The whole process felt unreliable and I ended up doubting the accuracy of the results. I would not use this test again.