What it is: A stool culture detects and identifies bacteria causing lower digestive tract infections, distinguishing disease-causing (pathogenic) bacteria from the normal flora that naturally lives in the gut.
Why it's ordered: Providers typically order it for prolonged diarrhea (>3 days), bloody diarrhea, mucus in stool, abdominal pain/cramping, or nausea — especially with recent travel or a shared illness pattern with someone close to the patient. It's often paired with a broader PCR-based GI pathogens panel or a separate ova-and-parasite exam.
What it detects: Bacteria like Campylobacter, Salmonella, Shigella, and Vibrio cholerae, plus certain parasites (Giardia, Cryptosporidium). C. difficile is usually tested separately via toxin/antigen assay rather than standard culture, since it often overgrows after antibiotics suppress competing normal flora.
Collection & prep: Fresh sample collected in a clean container, free of urine/water contamination; must reach the lab within ~2 hours or be placed in a preservative vial, since delayed/unpreserved samples distort bacterial proportions. Patients should avoid barium or bismuth for 7–10 days before collection; otherwise no special prep is needed.
Negative – no pathogens found; symptoms may be non-infectious
Inconclusive – may require repeat testing
Possible complications of bacterial GI infection: Dehydration/electrolyte imbalance from prolonged diarrhea (risk highest in children/elderly); rarely, hemolytic uremic syndrome (red blood cell destruction and kidney failure) from certain toxin-producing strains.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
