Editing Hashimoto's thyroiditis (section)

==== Inadequate markers hypothesis ====
There is ongoing debate about how to define euthyroidism and whether TSH is its best indicator.<ref name="Jonklaas-2019" /> TSH may be useful to detect poor thyroid output and may reflect the state of thyroid hormones in the [[Hypothalamic–pituitary–thyroid axis|hypothalamic-pituitary-thyroid axis]], but not the presence of hormones in other body tissues.<ref name="Hegedüs-2022" /><ref name="Taylor-2024" /><ref name="Wiersinga-2014" /> As a result, LT<sub>4</sub> monotherapy may not result in a "truly biochemically euthyroid state."<ref name="Groenewegen-2021" /> Patients may express a preference for "low normal or below normal TSH values"<ref name="Wiersinga-2014" /> and/or T<sub>4</sub> and T<sub>3</sub> monitoring. The monitoring of other [[Biomarker (medicine)|biomarkers]] that reflect the action of thyroid hormone on tissues has also been proposed.<ref name="Klubo-Gwiezdzinska-2022" /><ref>{{cite journal | vauthors = McAninch EA, Rajan KB, Miller CH, Bianco AC | title = Systemic Thyroid Hormone Status During Levothyroxine Therapy In Hypothyroidism: A Systematic Review and Meta-Analysis | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 103 | issue = 12 | pages = 4533–4542 | date = August 2018 | pmid = 30124904 | pmc = 6226605 | doi = 10.1210/jc.2018-01361 }}</ref><ref name="Hegedüs-2022" />

As [[immunoassay]] Free T<sub>3</sub> and Free T4 tests can overestimate levels, particularly at low thyroid hormone levels, hypothyroidism may be undertreated.<ref name="Welsh-2016" /> [[Liquid chromatography–mass spectrometry|LC-MSMS]] tests may provide more reliable measures.<ref name="Welsh-2016" />