When hyperthyroidism is suspected, diagnosis is normally very straightforward.
In most cases, your veterinary surgeon will be able to feel the enlarged thyroid lobes in your cat’s neck.
Occasionally, the thyroid gland cannot be easily felt. This happens when the thyroid tissue is located elsewhere, usually inside your cat’s chest.
To confirm the diagnosis your veterinary surgeon will arrange a blood test in order to measure levels of the T4 hormone. Although both the T4 and T3 hormones are produced in excess, measuring the total T4 level is the most accurate test available.
Since most cats with hyperthyroidism are older, it is recommended that your cat has other blood tests to assess their organ function and make sure that they do not suffer from any other problems. Kidney disease, although not directly linked to hyperthyroidism, may develop at the same time since both diseases are common in older cats.
Blood tests are important because other conditions might affect the successful treatment of hyperthyroidism.