Occult Blood (FOBT)
- Sample Type
- Standard
- Fasting
- No
- Unit
- Interpretation
The Fecal Occult Blood Test (FOBT) is a biochemical analysis used to detect the presence of hemoglobin in the stool that is not visible to the naked eye. Within a Complete Stool Examination, it serves as a primary screening tool for gastrointestinal (GI) bleeding. Chronic, low-volume bleeding can be an early indicator of colorectal polyps, colorectal cancer, diverticulitis, or inflammatory bowel disease (IBD). Since many colorectal lesions bleed intermittently, this test is critical for identifying pathologies before they become symptomatic.
Why Context Matters
False positives are extremely common due to dietary intake of red meat, certain vegetables (broccoli, turnips), or medications like NSAIDs and aspirin which can cause minor gastric irritation. Conversely, false negatives can occur if a lesion is not bleeding at the time of sample collection. A second opinion or follow-up colonoscopy is often necessary to confirm the source of the blood.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Occult Blood (FOBT):
Official Sources
- Fecal occult blood test - Mayo ClinicMayo Clinic
- Fecal Occult Blood Test - Testing.comTesting.com
Research & Guidelines
- PubMed: Occult Blood (FOBT) Clinical GuidelinesNCBI / PubMed
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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