welche blutwerte bei müdigkeit — which blood markers matter?

For fatigue, several blood markers are relevant, depending on accompanying symptoms and risk factors. From the provided context: thyroid parameters (TSH, possibly fT3/fT4) – a home TSH test gives only a rough screening value and is not diagnostic (evidence: practice). Hormone panel for men (testosterone, SHBG, LH, prolactin) – a single low result is insufficient due to daily fluctuations and lack of free testosterone measurement (evidence: practice). Vitamin K deficiency (rare) can be detected via clotting parameters (Quick, INR) but is not a common cause (evidence: human-observational). Standard markers like complete blood count (Hb, MCV), ferritin, vitamin B12, folate, CRP, glucose, and HbA1c are routinely recommended but not explicitly mentioned in the context. Caveat: fatigue has many causes (sleep, mental health, nutrition, infections). No single lab value is sufficient alone. The evidence for these markers is mostly practice-based (screening) and not backed by strong clinical trials. Consult a physician for a full workup if fatigue persists.