Can illness affect thyroid function test results?

Yes, illness can temporarily affect your thyroid function test results. Acute or chronic illnesses, such as infections or autoimmune diseases, can influence TSH levels. This phenomenon is called euthyroid sick syndrome, where the thyroid hormone levels appear abnormal despite the absence of true thyroid dysfunction. Your doctor will consider your overall health and the presence of any acute conditions when interpreting TFT results. If you're unwell at the time of the test, it’s advisable to inform your healthcare provider.