TSHSpiegels

TSHSpiegels (TSH levels) refer to the concentration of thyroid-stimulating hormone in the blood. TSH is produced by the pituitary gland and regulates thyroid hormone production by stimulating the thyroid to release T4 and T3. The release of TSH is controlled by thyrotropin-releasing hormone (TRH) from the hypothalamus and by negative feedback from circulating thyroid hormones. TSH exhibits slight diurnal variation and can be influenced by illness, stress, medications, and pregnancy.

In clinical practice, TSH testing is the primary screening tool for thyroid function and is often measured together with free T4. Most laboratories use age- and assay-specific reference ranges; a common adult reference range is roughly 0.4–4.0 mIU/L, though ranges may differ by lab and population. Pregnancy, age, and certain medical conditions can shift expected values, and pediatric ranges differ from adults.

Interpretation of TSH results depends on the accompanying free thyroid hormone levels. A high TSH with a normal or low free T4 suggests primary hypothyroidism, whereas a low TSH with a high free T4 suggests hyperthyroidism. Subclinical forms exist when TSH is outside the reference range but free T4 remains normal. Subclinical hypothyroidism or hyperthyroidism may warrant monitoring or treatment based on symptoms, age, pregnancy status, and associated health risks. Autoimmune thyroid disease, pituitary disorders, and medications can also affect TSH.

Measurement of TSH is most informative when interpreted with other thyroid tests, particularly free T4, and in the context of clinical findings. Accurate interpretation requires consideration of laboratory-specific reference ranges and patient-specific factors.