What would indicate hyperthyroidism in terms of TSH levels?

In the context of hyperthyroidism, low TSH (Thyroid-Stimulating Hormone) levels are indicative of the condition. Hyperthyroidism occurs when the thyroid gland is overactive, producing excess thyroid hormones (T3 and T4). When these hormones are elevated, they provide negative feedback to the pituitary gland, leading to a decreased secretion of TSH.

As a result, when someone is experiencing hyperthyroidism, the expected laboratory finding would be low levels of TSH, often accompanied by high levels of T3 and T4. Understanding this feedback mechanism is crucial for interpreting thyroid function tests and diagnosing thyroid disorders accurately. Other options, like high, normal, or variable TSH levels, do not represent the characteristic findings of hyperthyroidism, as they do not align with the expected physiological response to elevated thyroid hormone levels.