A nurse is reviewing the medical record of a client who has hyperthyroidism (Graves' disease). Which of the following serum laboratory findings should the nurse expect to be below the expected reference range?

A. Thyroid stimulating hormone (TSH) level: In primary hyperthyroidism (Graves’ disease) high T3/T4 exert negative feedback on the pituitary, resulting in a suppressed (low) TSH. B. Triiodothyronine (T3) level: T3 is typically elevated in hyperthyroidism rather than below the reference range. C. Glucose level: Serum glucose can be normal or elevated due to increased metabolism; a low glucose is not a classic finding of hyperthyroidism. D. Thyroxine (T4) level: T4 is generally elevated in hyperthyroidism rather than decreased.