A screening test that detects blood in the stool that is not visible to the naked eye. It is used for the early diagnosis of colorectal cancer and bleeding from the digestive tract.
Indication
- Colorectal cancer screening in individuals over 50 years of age
- Early screening in those with a family history of colon cancer
- Investigation of unexplained iron deficiency anemia
- Weight loss and changes in bowel habits
- Evaluation of abdominal pain and bloating complaints
- Suspicion of rectal bleeding from causes other than hemorrhoids
- Screening before colonoscopy
Preparation
- A special diet is generally not required for the FIT (immunochemical) test
- For the traditional guaiac (FOBT) test, red meat, radishes, broccoli, and vitamin C are not recommended starting 3 days beforehand
- The use of aspirin and blood thinners is reported to the physician
- Samples are not collected during menstruation
- If active hemorrhoidal bleeding is present, the test is postponed
How it's performed
- A stool container is obtained from the laboratory
- Stool samples may need to be collected on three separate days (FOBT)
- For the FIT test, a single sample is generally sufficient
- Samples are quickly delivered to the laboratory
- In the laboratory, blood is detected by chemical or antibody-based methods
- The result is reported as positive or negative
Post-procedure
- If the result is negative, screening is recommended every 1-2 years
- If positive, a detailed examination is performed with colonoscopy
- A single positive result does not mean cancer; polyps, hemorrhoids, or other causes may be responsible
- The physician may request additional tests in light of clinical findings
Risks
- There is no procedural risk (the sample is collected by the patient)
- False-positive result (red meat, certain medications)
- False-negative result (bleeding may be intermittent)
- It may not be sufficient on its own; clinical evaluation is required
FAQ
Does a positive result mean I have cancer?
No. A positive result indicates bleeding in the digestive tract; the cause may be hemorrhoids, polyps, or other benign conditions. A detailed examination is performed with colonoscopy.
At what age should screening begin?
The general recommendation is regular screening from age 50 onward. Those with a family history may begin from age 40.
What is the difference between FIT and FOBT?
FIT (immunochemical) detects only human hemoglobin and does not require dietary restriction. FOBT (guaiac) is the older method and requires dietary preparation.
Can the test be performed if I have hemorrhoids?
If there is active bleeding, the test is postponed because it leads to false-positive results. It can be performed after the hemorrhoids have been treated.
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