How to Measure Thyroid Levels

Thyroid levels are measured using a blood, urine or breath test to check levels of the hormones TSH, T3 and T4. TSH, which is produced by the pituitary gland, triggers the thyroid's production of T4, also known as thyroxine. T4 is then converted to triiodothyronine, or T3. The lack of these hormones---or insufficient levels of them---could result in hyperthyroidism, hypothyroidism primary or hypothyroidism secondary. Determining if the thyroid is functioning properly requires a blood test to measure all three hormones.

Instructions

• 1

  Monitor your mood, weight gain, and levels of tiredness, and keep a record of them. If you seem to be more depressed than normal, are gaining or losing weight, or are extremely tired, schedule an appointment with your doctor, who may decide to check thyroid levels.

• 2

  Explain your symptoms to your doctor.

• 3

  Provide a blood sample to your doctor. Tests will measure T3, T4 and TSH levels.

• 4

  Obtain the test results and review them with your doctor. Test results showing high TSH levels indicate primary hypothyroidism. Results showing low TSH levels indicate hyperthyroidism. A measure of T4 and TSH levels together may reveal how the thyroid gland is functioning. It may also indicate whether problems are related to the pituitary gland or to the thyroid gland. T3 results are most useful in diagnosing hyperthyroidism and determining its severity.