Sorry for the delay. It was 3 hours before you answered and I was off line for the day.
Interesting questions, I will explain further.
It means that they depressed thyroid function is sub clinical if you have no symptoms. if you have symptoms, such as weight gain, mental sluggishness, then it is clinical hypothyroidism.
There is no such term as thyroid failure, just an increasing degree, gradually, of low function.
We treat if there are symptoms and a TSH above 2.5 [international guidelines] or if there is a TSH over normal according to all guidelines, which is 4.2 to 4.5.
OK, let me know if you have more questions.
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