Thyroid disease examination

Serum TSH

 * Its concentration is inversely proportional to the concentration of T4,
 * assuming normal function of the hypothalamo-pituitary axis reflects the level of T4,
 * significantly increased: primary hypothyroidism,
 * sometimes a modified version is produced - it is also possible to find out
 * method of first choice when primary hypothyroidism or hyperthyroidism is suspected,
 * monitoring T4 replacement therapy,
 * is examined in hypercholesterolemia and hyperprolactinemia.

Functional test with TRH

 * Reflects TSH secretion,
 * in central hypothyroidism, in TSH-producing tumors.

Total thyroxine (TT4) and free (FT4) in serum

 * Indicators of current secretion,
 * FT4 indicates the availability of the hormone to the tissue,
 * free thyroxine index - FTI.
 * $$FTI=\frac{concentration\ T4 \cdot %T3-Uptake}{100}\ $$


 * Priority in the treatment of hyperthyroidism, TSH secretion can still be suppressed in the long term.

Serum total (TT3) and free (FT3) triiodothyronine

 * High levels of T3 during thyroxine treatment – ​​autonomous hyperactivity of the gland,
 * indication – examination of hyperthyroidism, severity of primary hypothyroidism, differential diagnosis of low TSH values.

Reverse T3 (RT3)

 * Indirect indicator of conversion of T4 to T3,
 * investigation of unknown causes of low TT3 or TT4.

Serum Thyroglobulin (TG)

 * Indicator of TG release from an active, inflammatory or tumor gland,
 * follow-up of patients after thyroidectomy for differentiated ca as a tumor marker - diagnosis of relapse (rising TG).

α-subunit of hCG

 * In general, they detect the formation of molecules with this subunit - also TSH.

Calcitonin, serum thyrocalcitonin

 * Indicator of secretory activity of C-cells thyroid glands,
 * in the diagnosis of medullary tumors.

Thyroxine binding globulin (TBG) in serum

 * Quantitatively the most significant carrier,
 * high values: genetically, during pregnancy, with contraception,
 * low concentrations: malnutrition, malabsorption, hepatic synthesis disorders,
 * we investigate T3 and T4 values, which do not correlate with the clinical condition.

Prealbumin, transthyretin in serum

 * The second most important transmitter.

Binding capacity of transport proteins, T-uptake

 * Meaning and indications as for TBG, we saturate the serum sample with a known concentration of T3 and determine the unbound fraction.

Antibodies against thyroperoxidase (Thyreoperoxidase Antibodies, TPOAb)

 * Previously described as antimicrosomal,
 * reveal the presence of an autoimmune process, a possible risk of dysfunction,
 * indication: goiter of unknown etiology, differential diagnosis of hyperthyroidism,
 * risk screening after birth.

Thyroglobulin antibodies

 * They reveal the autoimmune process, can explain incorrect results of TGB determination,
 * monitoring of differentiated carcinomas of the thyroid gland.

Antibodies against TSH receptors

 * They can either stimulate or inhibit,
 * risk of developing Graves disease, risk of endocrine ophthalmopathy,
 * differential diagnosis of hyperthyroidism.

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