3 doctors weighed in:

What are the causes of false negative results in stool blood testing?

3 doctors weighed in
Dr. Diane Minich
Family Medicine

In brief: Raw meat

Blood from undercooked meat and certain foods, .

In brief: Raw meat

Blood from undercooked meat and certain foods, .
Dr. Diane Minich
Dr. Diane Minich
Thank
Dr. Joseph De santi
Family Medicine

In brief: Bogus Testing

To be falsely negative would imply the presence of blood that has been missed.
Such an event commonly occurs with either a defective card, expired solution or poor sample. Try using a different card and solution. If there is a high suspicion of blood based on appearance or risk factors, a stool cell count can be done, a reagent test dropped into toilet water after defecating or fecal dna test.

In brief: Bogus Testing

To be falsely negative would imply the presence of blood that has been missed.
Such an event commonly occurs with either a defective card, expired solution or poor sample. Try using a different card and solution. If there is a high suspicion of blood based on appearance or risk factors, a stool cell count can be done, a reagent test dropped into toilet water after defecating or fecal dna test.
Dr. Joseph De santi
Dr. Joseph De santi
Thank
1 comment
Dr. Arthur Heller
High dose vitamin C (500mg or more) can cause false negatives. Remember that lesions may not bleed every day, so that any individual stool specimen may be negative, even in the setting of a true abnormality (lesion).. To screen for a colon cancer, need repeated stool tests, and/or use other tests, like colonoscopy..
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