If T3 and T4 increase and Tsh decreases in the five tests, it means hyperthyroidism; If T3 and T4 decrease and TSH increases, it means hypothyroidism. If T3 or T4 is abnormal alone, it is generally of little significance and needs to be checked regularly.
Extended data:
Precautions:
RT3 increased in hyperthyroidism, and decreased in hypothyroidism, chronic lymphocytic thyroiditis and simple goiter.
Propylthiopyrimidine, propranolol and amiodarone are known to inhibit the transformation from T4 to T3, but increase the transformation to rT3, thus increasing rT3.
The decline of T3 in patients with hypothyroidism lags behind that of T4. In low T3 syndrome, rT3 (anti-T3) is obviously increased, while TSH is not, which can be distinguished from hypothyroidism. The determination of T3 is also influenced by TBG.
HyperT4 will appear in a very small number of patients with mental illness and some non-thyroid diseases. Androgen can reduce TBG and T4, which leads to low T3 syndrome. In severe cases, T4 will also decrease. If T4 is significantly reduced, it indicates that the condition is critical and the prognosis is poor.
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