Free T3 and Free T4 Blood Tests

[supressedtsh]

At a BTF meeting I listened to a talk about thyroid blood tests from a person who was in charge of the laboratories.

I would like to ask the experts here the same question as I asked at the BTF meeting - why is the Free T4 blood test not done when the TSH is within range?

Why can we only have our Free T3 tested when an Endocrinologist requests it?

When treating hypothyroidism it is ridiculous to monitor the patient by the TSH. The TSH can be affected by so many things. The Free T4 gives a far better picture.

[Dr Petros Perros]

If one is screening for hypothyroidism and only relies on the serum TSH, patients with hypopituitarism (a very rare diagnosis) will be missed. It is for this reason that the BTF recommends that both teh serum TSH and FT4 should be measured if a diagnosis of hypothyroidism is suspected. Patiens who are already known to be hypothyroid and are on thyroxine can be adequately monitored by measuring the serum TSH alone.