wann ist eine stuhlprobe unbrauchbar — what symptoms are typical?

A stool sample is unusable if it has been improperly stored or transported (e.g., >24 h at room temperature, direct sunlight, freezing without preservative). Contamination with urine, water, or toilet paper also invalidates it. Symptoms like diarrhea or visible blood do not automatically disqualify the sample but may affect certain analyses – suitability depends on the test purpose. For microbiome tests, recent antibiotic use (4–6 weeks) and acute gastrointestinal infections are typical exclusion criteria. The sample must be of sufficient quantity (at least pea-sized). Missing or incorrect labeling also renders it unusable. Evidence is based on laboratory practice and manufacturer instructions, not clinical trials. When in doubt, consult the lab or a physician.