After discovering a thyroid nodule during a physical examination, what is the most appropriate next step?

The most appropriate next step after discovering a thyroid nodule during a physical examination is to assess the patient's serum TSH (thyroid-stimulating hormone) level. This initial evaluation is crucial because the TSH level helps determine the functional status of the nodule and guides subsequent diagnostic steps. A normal or elevated TSH level generally indicates that the nodule may be non-functional (not producing excess thyroid hormone), while a suppressed TSH level could suggest that the nodule is hyperfunctioning and potentially benign.

Understanding the TSH level informs the clinician about whether further imaging, such as a thyroid scan, is necessary or if a fine needle aspiration biopsy is warranted based on the characteristics of the nodule and the patient's risk factors. Overall, measuring serum TSH is a foundational step in the evaluation process and assists in deciding the most appropriate and timely management for the patient.