Which laboratory finding would not be expected in Graves disease?

Which laboratory finding would not be expected in Graves disease?

• A. Antibody to TSH receptor
• B. Increased TSH levels
• C. Elevated T3/T4
• D. Antithyroglobulin antibodies

Answer: (B)

In Graves disease, the immune system produces antibodies that stimulate the TSH receptor on thyroid cells, driving the gland to make more thyroid hormones. This excess of T3 and T4 feeds back to the pituitary, which lowers TSH production. So you typically see high thyroid hormone levels with suppressed (low) TSH. That’s why increased TSH would not be expected. The presence of antibodies to the TSH receptor is common and explains the stimulation, thyroid hormone levels are elevated, and antithyroglobulin antibodies can also be present in autoimmune thyroid diseases.

In Graves disease, the immune system produces antibodies that stimulate the TSH receptor on thyroid cells, driving the gland to make more thyroid hormones. This excess of T3 and T4 feeds back to the pituitary, which lowers TSH production. So you typically see high thyroid hormone levels with suppressed (low) TSH. That’s why increased TSH would not be expected. The presence of antibodies to the TSH receptor is common and explains the stimulation, thyroid hormone levels are elevated, and antithyroglobulin antibodies can also be present in autoimmune thyroid diseases.