Understanding Fecal Occult Blood Test (FIT) and Related Markers
Learn about the Fecal Occult Blood Test (FIT) and its related markers, how to interpret results, and when to consult a doctor.
The Fecal Occult Blood Test (FIT) is a screening tool used to detect hidden blood in the stool, which may be an early sign of colorectal cancer or other gastrointestinal issues. Understanding FIT results and how they relate to other markers can help you and your healthcare provider make informed decisions about your health.
What is the Fecal Occult Blood Test (FIT)?
The Fecal Occult Blood Test (FIT) is a non-invasive test that checks for hidden (occult) blood in the stool. Occult blood is not visible to the naked eye but can indicate bleeding in the digestive tract. FIT is commonly used in colorectal cancer screening programs because it can detect small amounts of blood that might be an early sign of cancer or polyps, which are growths that can develop into cancer over time.
Why is FIT Important?
FIT is crucial because it helps detect colorectal cancer at an early stage when treatment is more likely to be successful. Colorectal cancer is one of the most common types of cancer, and early detection through screening can significantly improve outcomes. By identifying hidden blood in the stool, FIT can prompt further diagnostic testing, such as a colonoscopy, to determine the cause of bleeding.
How to Read FIT Results and Related Markers
FIT results are usually reported as positive or negative. A positive result means that blood was detected in the stool sample, while a negative result means no blood was found. However, a positive result does not necessarily mean cancer is present. It indicates that further investigation is needed to identify the source of bleeding.
Related Markers
- Hemoglobin: This is the protein in red blood cells that carries oxygen. In the context of FIT, the presence of hemoglobin in the stool is what the test detects.
- Hematocrit: This measures the proportion of blood volume that is occupied by red blood cells. Low hematocrit levels can indicate anemia, which may be related to bleeding detected by FIT.
- Ferritin: This is a protein that stores iron in the body. Low ferritin levels can suggest iron deficiency anemia, which may be due to chronic blood loss in the gastrointestinal tract.
Factors That Can Affect FIT Results
Several factors can influence FIT results, including dietary choices and medications. Unlike older fecal occult blood tests, FIT does not require dietary restrictions before testing. However, certain medications, such as aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), can increase the risk of bleeding and may affect test results. Always inform your healthcare provider about any medications you are taking before undergoing a FIT.
Frequently Asked Questions
What should I do if my FIT result is positive?
A positive FIT result means that blood was detected in your stool. It does not necessarily indicate cancer but does require further investigation. Your healthcare provider may recommend additional tests, such as a colonoscopy, to determine the cause of bleeding.
Can a negative FIT result rule out colorectal cancer?
A negative FIT result means no blood was detected in your stool at the time of the test. While this reduces the likelihood of colorectal cancer, it does not entirely rule it out. Regular screening as recommended by your healthcare provider is important.
How often should I have a FIT?
The frequency of FIT screening depends on your risk factors and your healthcare provider's recommendations. Typically, it is recommended annually for individuals at average risk starting at age 50.
Are there any risks associated with FIT?
FIT is a safe, non-invasive test with no direct risks. However, a positive result may lead to additional procedures, such as a colonoscopy, which carry their own risks.
Can diet affect the FIT results?
Unlike some older fecal occult blood tests, FIT does not require dietary restrictions, making it more convenient and reliable.
When to See a Doctor
You should see a doctor if you receive a positive FIT result, as further testing is needed to determine the cause of bleeding. Additionally, if you experience symptoms such as persistent abdominal pain, changes in bowel habits, or unexplained weight loss, it is important to consult a healthcare provider regardless of your FIT result.
Remember, while FIT is a valuable screening tool, decisions about your health should always be made in consultation with a healthcare professional.
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This explainer is queued for our doctor panel and hasn't been individually reviewed yet. It's general information, drawn from standard references - always confirm decisions with your own clinician.