What laboratory value is expected to be elevated in a patient with hyperthyroidism?

In a patient with hyperthyroidism, an elevated level of free triiodothyronine (FT3) is expected. Hyperthyroidism is characterized by an overproduction of thyroid hormones, including both thyroxine (T4) and triiodothyronine (T3). FT3 is the biologically active form of T3, and when the thyroid gland is hyperactive, the levels of FT3 in the bloodstream rise significantly.

The increase in FT3 leads to various symptoms associated with hyperthyroidism, such as weight loss, increased heart rate, and heat intolerance, due to the heightened metabolic state induced by the excess thyroid hormones. Monitoring FT3 levels can be crucial for diagnosing and managing hyperthyroidism effectively.