Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX
For a patient suspected of having hyperthyroidism, the initial investigations involve thyroid function tests (TFTs) NICE NG145.
- For adults where secondary thyroid dysfunction (pituitary disease) is not suspected, consider measuring thyroid-stimulating hormone (TSH) alone NICE NG145. If the TSH level is below the reference range, then measure free thyroxine (FT4) and free tri-iodothyronine (FT3) from the same sample NICE NG145.
- For adults where secondary thyroid dysfunction (pituitary disease) is suspected, or for children and young people, consider measuring both TSH and FT4 initially NICE NG145. If the TSH is below the reference range, measure FT3 in the same sample NICE NG145.
It is important to note that testing for thyroid dysfunction should generally not be done during an acute illness, unless the acute illness itself is suspected to be due to thyroid dysfunction, as acute illness can affect test results NICE NG145. Additionally, always ask patients about their biotin intake, as high consumption from dietary supplements can lead to falsely high or low test results NICE NG145. If symptoms worsen or new symptoms develop, consider repeating the thyroid function tests, but no sooner than 6 weeks from the most recent test NICE NG145.