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

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.

Raw meat: Blood from undercooked meat and certain foods, .