In suspected Graves disease, which laboratory profile would you expect for FT4, THBR, and TSH?

In suspected Graves disease, which laboratory profile would you expect for FT4, THBR, and TSH?

• A. Increased, decreased, increased
• B. Increased, decreased, decreased
• C. Increased, Increased, Decreased
• D. Decreased, Decreased, Increased

Answer: (C)

Graves disease drives the thyroid to produce more hormone, so the amount of free thyroid hormone in the blood rises, reflected by an increased FT4. That excess hormone feeds back to the pituitary and tells it to slow down TSH production, so TSH falls. The THBR, which tracks how thyroid hormone availability and binding are affected in the system, also tends to rise in hyperthyroidism due to the overall increase in circulating hormone relative to binding dynamics. So the pattern you’d expect is higher FT4, higher THBR, and lower TSH.

Graves disease drives the thyroid to produce more hormone, so the amount of free thyroid hormone in the blood rises, reflected by an increased FT4. That excess hormone feeds back to the pituitary and tells it to slow down TSH production, so TSH falls. The THBR, which tracks how thyroid hormone availability and binding are affected in the system, also tends to rise in hyperthyroidism due to the overall increase in circulating hormone relative to binding dynamics. So the pattern you’d expect is higher FT4, higher THBR, and lower TSH.