A Hemoccult test checks stool for hidden (occult) blood. Sometimes the test is positive even when there is no serious problem. This is called a false positive.
Many Hemoccult tests—including those processed using **Beckman Coulter systems—are very sensitive, which means they can react to things other than true bleeding.
Common Reasons for a False-Positive Result
Certain foods eaten before the test.
Some foods can cause the test to turn positive even when there is no bleeding.
Avoid these for 3 days before testing:
- Red meat (beef, lamb, liver)
- Broccoli, cauliflower, turnips
- Horseradish
- Parsnips
- Cantaloupe
Medications and supplements
Some medicines can irritate the digestive tract or affect the test result:
- Aspirin or other NSAIDs (ibuprofen, naproxen)
- Steroids (such as prednisone)
- Iron supplements
- High-dose vitamin C
Do not stop prescribed medications unless your clinician tells you to.
Minor, non-serious bleeding
Small amounts of blood from non-GI sources can cause a positive test:
- Hemorrhoids
- Anal fissures
- Swallowed blood from a nosebleed
- Bleeding gums or recent dental work
Menstrual contamination
Testing during menstruation can cause a false positive. Avoid testing during your period and for 3 days after it ends
Collection or handling issues
- The test can be affected by:
- Using expired test cards
- Collecting stool from toilet water
- Using too much stool on the card
- Improper storage or delayed processing
What a Positive Test Does Not Automatically Mean
- A positive Hemoccult test does NOT automatically mean:
- Colon cancer
- A serious intestinal diseas
- That you are bleeding internally
Many positive results are explained by diet, medications, or minor causes.
What Usually Happens Next
Depending on your situation, your clinician may:
- Repeat the test with better preparation
- Order a FIT test (a newer stool test that is more specific)
- Review your blood counts and iron levels
- Recommend further testing only if needed
