The five indicators of thyroid testing include thyroid stimulating hormone, free serum T3 and T4, and total serum thyroxine T3 and T4. Monitoring the range of these five indicators during thyroid testing can help determine whether you have hyperthyroidism or hypothyroidism, as well as other thyroid disorders, which are mostly secreted by the epithelial follicular cells of the thyroid gland. A high TSH level in the test results indicates a high level of thyroid stimulating hormone released from the pituitary gland, while a low level of thyroid hormone in the body itself may indicate hypothyroidism, with clinical symptoms such as reduced gastrointestinal function, mental indifference, loss of appetite, and reduced heart rate.