Thyroid function tests for the diagnosis of suspected primary or secondary thyroid dysfunction
Thyroid function tests are used for the diagnosis and monitoring of patients with thyroid disorders. Most guidelines recommend a two-step testing approach: TSH should be measured first, only followed by a measurement of (free[f]) T4/(f)T3, if TSH is out of the reference range or if there is clinical suspicion of abnormal TSH secretion. However, it is observed that TSH and (f)T4/(f)T3 are often measured together in a one-step test approach. The argument in favour of the one-step approach is prevention of missed diagnosis of patients with normal TSH levels and thyroid hormone levels outside the reference range.
The objective of this HTA report is to evaluate the available clinical and economic evidence associated with the one-step and the two-step test approaches in adults with suspected primary or secondary thyroid dysfunction.