Can a thyroid function test detect thyroid cancer?

A thyroid function test (TFT) cannot directly diagnose thyroid cancer, as most thyroid cancers do not significantly affect thyroid hormone levels. However, TFTs are used to rule out other thyroid disorders, like hyperthyroidism or hypothyroidism, which may present with similar symptoms. If your doctor suspects thyroid cancer, they may order additional tests such as a thyroid ultrasound, fine-needle aspiration biopsy, or radioactive iodine scans to check for abnormal nodules or masses in the thyroid gland.