Few investigations are requested as frequently, or interpreted as variably, as thyroid function tests. Since the earliest descriptions of thyroid disease in the late 19th century, clinicians have grappled with linking biochemical abnormalities to clinical states. In modern practice, TFTs are routinely ordered across all levels of care, yet their interpretation remains anything but straightforward.



Abnormal results may reflect intrinsic thyroid pathology, transient inflammatory processes, systemic illness, or adaptive physiological responses. This complexity can contribute to diagnostic uncertainty, inappropriate treatment, and unnecessary patient anxiety. Conditions such as subclinical hypothyroidism & hyperthyroidism, thyroiditis and non-thyroidal illness are all seen in everyday clinical practice. Navigating conflicting evidence and evolving guideline recommendations adds another layer of challenge for clinicians striving to make sound decisions.