The diagnosis of hyperthyroidism

Diagnosis of feline hyperthyroidism is usually very straightforward. In the majority of cases, a veterinary surgeon will be able to feel the enlarged thyroid lobe(s) in the neck. Sometimes the thyroid gland cannot be felt because the overactive thyroid tissue is located elsewhere, usually inside the chest.

Blood samples taken from a cat to measure the level of T4 (total T4 blood test) will usually confirm the diagnosis.

As most cats with hyperthyroidism are older, routine blood tests to assess organ function are also recommended to make sure that no other conditions will affect the success of treatment.