1st-order laboratory parameters-obligatory laboratory tests.
- TSH (thyroid-stimulating hormone)* [TSH level > 4 mU/l → repeat measurement for confirmation].
- FT4 (thyroxine) [within normal range]
* Latent hypothyroidism: TSH value > 4 mU/l + fT4 in the normal range.
Note: In latent hypothyroidism, thyroid levels are determined again after 4-8 weeks.
2nd order laboratory parameters – depending on the results of the medical history, physical examination, etc. – for differential diagnostic clarification
- TRH-TSH test – thyroid function diagnostics.
- TPO antibodies (TPO-Ak; thyroid peroxidase; MAK) – for diagnosis of autoimmune thyroid diseases such as Hashimoto’s thyroiditis (autoimmune thyroiditis); initially with increased secretion of thyroid hormones, later with gradual transition to hypothyroidism. MACs are found:
- Slightly elevated in: Goiter, functional autonomy, other autoimmune diseases.
- Markedly elevated in: Hashimoto’s thyroiditis (autoimmune thyroiditis Hashimoto) (> 90%), primary myxedema, Graves’ disease (70%).
- Tg antibodies (Tg-Ak; thyroglobulin autoantibodies (TGAK); thyroglobulin-Ak; TAK) – for the diagnosis of autoimmune thyroid diseases such as Hashimoto’s thyroiditis.
- TSH receptor antibodies (TRAK).
- Prolactin – hormone responsible for mammary gland growth and lactation (milk secretion).
Other notes
- With increasing BMI (body mass index) and waist circumference, TSH levels increase
- Amiodarone, domperidone, dopamine antagonists, metoclopramide, and sulpiride may cause TSH levels to increase:
