Is Stuhlprobe useful for fatigue?

Whether a stool test (e.g., microbiome analysis) is useful for fatigue cannot be clearly answered with 'yes' based on current evidence. While there are indications that the gut microbiota can influence energy and mood via the gut–brain axis, the evidence for a causal link with general fatigue is weak and mostly correlational. Most commercial stool tests merely list bacterial species without validated clinical reference ranges for fatigue. Moreover, fatigue has many potential causes (iron deficiency, sleep disorders, thyroid issues, psychological stress) that a stool test does not address. Therefore, such a test is not a diagnostic tool for fatigue but at best an exploratory instrument within a holistic assessment. The evidence level is 'mixed' or 'unclear'. Always consult a doctor before interpreting results.