Understanding TSH Levels: What They Mean for Your Thyroid Health

TSH levels are the amount of thyroid-stimulating hormone in a patient's bloodstream. Analyzing the levels helps doctors determine if the thyroid gland is working properly.

Identification

• Your doctor can measure TSH levels through a blood test. If the results indicate a problem with the thyroid, the doctor may order a radioactive iodine uptake test or a thyroid scan, says the Mayo Clinic.

Normal Levels

• According to the National Institutes of Health, normal TSH levels for an adult can be in the 0.4 to 4.0 milli-international units per liter (mIU/L) range. Abnormal TSH levels may indicate an under-active or overactive thyroid gland.

Significance

• According to the Mayo Clinic, patients with untreated hyperthyroidism (an overactive thyroid gland) may lose weight, and experience sweating or irritability. Hypothyroidism (under-active thyroid) can cause patients to gain weight, and increases the chance of heart disease, infertility and other health problems.

Other Factors

• Dye from a recent X-ray; long-term stress; or drugs such as corticosteroids, seizure medications and blood thinners can affect TSH levels, says the Mayo Clinic.

Additional Tests

• Additional tests, such as a T-3 (triiodothyronine ) or a T-4 (thyroxine) test, can clarify results or confirm unusual TSH levels.