1st-order laboratory parameters-obligatory laboratory tests.
- TSH (thyroid-stimulating hormone)* .
- FT4 (thyroxine)*
* Latent hyperthyroidism: TSH level < 0.3 mU/l + fT4 in the normal range.
Note: In latent hyperthyroidism, 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; synonyms: thyroid peroxidase, MAK) – for the 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.
- MAK find:
- Slightly elevated in: Goiter, functional autonomy, other autoimmune diseases.
- Markedly elevated in: Hashimoto’s thyroiditis (autoimmune thyroiditis Hashimoto) (> 90%), primary myxedema, Graves’ disease (70%).
If TRAK and MAK are found, then this speaks for M. Graves.
- Thyroglobulin antibodies (Tg antibodies; TAK) – for the diagnosis of autoimmune thyroid diseases such as Hashimoto’s thyroiditis.
- TSH receptor antibodies (TRAK) – for the detection of Graves’ disease [in the acute stage in 95% of cases TRAK].
Laboratory diagnostics in old ageLaboratory diagnostics in old age provides less clear information than in younger age:
- T4 → T3 conversion is decreased in old age.
- Thyroxine requirement is decreased in old age
Thus, the level of normal values of fT3 and fT4 is lower in old age, so that even the constellation of subclinical (latent) hyperthyroidism with high-normal peripheral hormone serum levels in individual cases can mean a manifest hyperthyroid metabolic situation.
