What tsh level is considered to be a sign of hypothyroidism?

It's controversial: There is broad consensus that a TSH between 0.3-2.5 is normal (assuming no pituitary problem exists), and broad consensus that TSH levels above 10 are abnormal and should be treated. A middle-of-the-road approach might be to say that levels between 5-10 are abnormal, and treatment is likely to be beneficial, and that values between 2.5-5 may be abnormal, and that treatment may be beneficial.

Every lab has : Normal ranges look at lab slip.