was ist tsh wert — when to see a doctor?

TSH (thyroid-stimulating hormone) is a key marker for thyroid function. Normal values typically range from 0.4 to 4.0 mIU/L, but reference intervals vary by laboratory, age, and individual health status. You should see a doctor if your TSH is outside this range: below 0.3 mIU/L suggests hyperthyroidism, above 4.5 mIU/L suggests hypothyroidism. Even borderline values (e.g., TSH 4.0–4.5) warrant medical evaluation if you experience symptoms like fatigue, unexplained weight changes, palpitations, cold intolerance, or mood disturbances. A single TSH value is not diagnostic; it must be interpreted alongside free T3, free T4, and possibly thyroid antibodies. This answer is based on standard clinical practice, not on the provided context (which contains no TSH-related information). Evidence level: practice. No fabricated sources.