Sub clinical hypothyroidism

Subclinical hypothyroidism is diagnosed with a blood test.

A person with a normal functioning thyroid should have a blood TSH reading within the normal reference range, which commonly goes up to 4.5 milli-international units per liter (mIU/L) or 5.0 mIU/LTrusted Source.

However, there’s debate underway in the medical community about lowering the highest normal threshold.

People with a TSH level above the normal range, who have normal thyroid gland hormone levels, are considered to have subclinical hypothyroidism.

Because amounts of TSH in the blood can fluctuate, the test may need to be repeated after a few months to see if the TSH level has normalized.

There’s a lot of debate about how — and even if — to treat those with subclinical hypothyroidism. This is especially true if TSH levels are lower than 10 mIU/L.

Because a higher TSH level can start to produce adverse effects on the body, people with a TSH level over 10 mIU/L are generally treated.

Evidence is mostly inconclusive that those with TSH levels between 5.1 and 10 mIU/L will benefit from treatment.

In deciding whether or not to treat you, your doctor will take into consideration things like:

your TSH level

whether or not you have antithyroid antibodies in your blood and a goiter (both are indications the condition may progress to hypothyroidism)

your symptoms and how much they’re affecting your life

your age

your medical history

When treatment is used, levothyroxine (Levoxyl, Synthroid), a synthetic thyroid hormone taken orally, is often recommended and is generally well tolerated.