wann ist eine stuhlprobe unbrauchbar — can a DNA test help?

The question of when a stool sample is unusable is not directly addressed in the provided knowledge context. In general, stool samples are considered unusable if contaminated with urine or water, not properly refrigerated (e.g., >24 h at room temperature), too old (>3 days), or if the patient recently took antibiotics, proton pump inhibitors, or antidiarrheals. Blood in the sample or insufficient quantity can also compromise analysis. A DNA test (like MyBody-X) cannot directly assess stool sample quality. However, it may indirectly help by identifying genetic risk factors for gut conditions (e.g., lactose intolerance, celiac disease) that affect stool consistency. The evidence for this is indirect, based on population genetic associations, not on sample quality. For evaluating the stool sample itself, laboratory standards (e.g., stool test kit instructions) and clinical criteria are decisive.