Hello there, Normal values range from 0.4 - 4.0 milli-international units per liter (mIU/L). Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results. If you are being treated for a thyroid disorder, your TSH level will likely be kept between 0.5 and 4.0 mIU/L... TSH values can vary during the day. It is best to have the test early in the morning...