welche blutwerte sind wichtig bei müdigkeit — when to see a doctor?

For persistent fatigue, several blood markers are clinically important before assuming a benign cause. These include: complete blood count (hemoglobin, MCV) to detect anemia, ferritin (iron stores), vitamin B12, folate, vitamin D, TSH (thyroid function), fasting glucose, and inflammatory markers like CRP. Iron deficiency without anemia can also cause fatigue. Vitamin D deficiency is common and linked to exhaustion, but evidence for a causal role is moderate. Important: These values should be interpreted by a doctor, as reference ranges vary individually. You should see a physician if fatigue lasts more than two weeks, is accompanied by unexplained weight loss, fever, night sweats, or a significant drop in performance. Also seek help if you have psychological symptoms like lack of drive or sleep disturbances. Caution: Supplements without a proven deficiency can cause side effects. Genetic tests for fatigue are mostly speculative and not clinically validated. Evidence for single SNPs like VDR or FUT2 is weak; blood tests and medical diagnostics are more reliable.