normal range for thyroid tests
If youâre making too much thyroid hormone, your TSH will go down.â. Whatâs normal can vary, depending on a number of factors, including the laboratory where your blood test is done, she adds. A normal range for TSH in most laboratories is 0.4 milliunits per liter (mU/L) to 4.0 mU/L.If your TSH is higher than 4.0 mU/L on repeat tests, you probably have hypothyroidism.hatâs normal can vary, depending on a number of factors, including the laboratory where your blood test is done, she adds. A normal range for TSH in most laboratories is 0.4 milliunits per liter (mU/L) to 4.0 mU/L.