Diagnosis can be done by 3 steps:-
The blood levels of thyroid hormones can be measured
directly and are usually elevated with this disease. However, the main tool
for detection of hyperthyroidism is measurement of the blood TSH level.
The blood tests will check the levels of TSH (thyroid stimulating hormone), T3 and T4 in the blood. These tests are known as thyroid function tests.
If the blood tests show levels of TSH are raised then the thyroid gland is underactive, this is because TSH levels rise to try to manufacture more T3 and T4.
If the thyroid is overactive and producing above normal levels of T3 and T4 then less TSH is produced
If inflammation of thyroid gland is suspected, an ultrasound scan of gland may be taken