How to interpret the results of thyroid function tests?

The results of thyroid function tests (TFTs) must always be interpreted in light of the clinical status of the patient: hypothyroid, euthyroid or hyperthyroid Awareness of the conditions and/or disorders that can be associated with different patterns of TFTs guides further investigation and management

Which is a better marker of thyroid function T3 or FT4?

Whilst free T3 (fT3) is measured, it is less relevant than free T4 (ft4). This is because the thyroid releases T4 and T3 at a ratio of about 20:1 respectively, with T3 mainly being produced by peripheral conversion of T4. As a result, T4 is a much better marker of thyroid function.

How is TRH measured in a thyroid function test?

Thyroid function tests (TFTs) Thyroid function tests (TFTs) refer to the following investigations: TRH is not measured as part of thyroid function tests, as it is only released locally between the hypothalamus and pituitary (so it is not present in representative quantities within the peripheral circulation).

What are the different types of thyroid tests?

9.  The tests used to investigate thyroid function can be grouped into:  Tests that establish whether there is thyroid dysfunction:  TSH, total T4 & total T3 measurements.

What does a free T4 test tell you about the thyroid?

Tests measuring free T4 – either a free T4 (FT4) or free T4 index (FTI) – more accurately reflect how the thyroid gland is functioning when checked with a TSH. The finding of an elevated TSH and low FT4 or FTI indicates primary hypothyroidism due to disease in the thyroid gland.

When to refer a patient for a thyroid test?

Referral to a specialist laboratory and/or endocrine service is required when anomalous or discordant TFTs cannot be readily explained by confounding intercurrent illness, medication or assay interference Disorders of thyroid function are common (estimated UK prevalence is 1–4%).

How to interpret the results of thyroid function tests? The results of thyroid function tests (TFTs) must always be interpreted in light of the clinical status of the patient: hypothyroid, euthyroid or hyperthyroid Awareness of the conditions and/or disorders that can be associated with different patterns of TFTs guides further investigation and management Which is…