Stool for Occult Blood
- Sample Type
- Stool
- Fasting
- No
- Unit
- N/A
Function
The Stool Occult Blood test (often abbreviated as FOBT or FIT) is a screening tool used to detect microscopic traces of blood in the stool that are not visible to the naked eye. 'Occult' means hidden. This test is a primary screening method for colorectal pathologies that cause slow, intermittent bleeding into the gastrointestinal tract.
Why it is Ordered
It is most commonly used as a routine screening for colorectal cancer in adults over the age of 45-50. It is also ordered when a patient has unexplained iron-deficiency anemia or changes in bowel habits but no visible blood in the stool.
Associated Conditions
- Colorectal Polyps: Precancerous growths that may bleed occasionally.
- Colorectal Cancer: Early-stage tumors often bleed into the lumen of the gut.
- Peptic Ulcers: Sores in the stomach or duodenum.
- Inflammatory Bowel Disease (IBD): Such as Crohn's disease or Ulcerative Colitis.
- Diverticulosis: Small pouches in the colon wall that can become inflamed and bleed.
Methodology
- Guaiac-based (gFOBT): Detects heme through a chemical reaction. Requires dietary restrictions.
- Immunochemical (FIT): Uses antibodies to detect human hemoglobin. It is more specific and does not require dietary changes.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
Guaiac-based tests are highly susceptible to interference. Consuming red meat, broccoli, turnips, or horseradish within three days of the test can cause a false positive. Conversely, high doses of Vitamin C (supplements or citrus) can cause a false negative. Furthermore, bleeding from hemorrhoids or menstrual blood can contaminate the sample, leading to a positive result that does not originate from the colon.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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