What test can help confirm subacute granulomatous thyroiditis by identifying multinucleated giant cells?

Fine needle aspiration is the test that can help confirm subacute granulomatous thyroiditis by identifying the characteristic multinucleated giant cells. In this condition, which is often associated with viral infections, the thyroid gland becomes inflamed and may develop granulomatous inflammation. When a fine needle aspiration is performed on the thyroid tissue, it allows for the collection of cells, which can then be examined microscopically. The presence of multinucleated giant cells, along with other inflammatory cells, provides strong evidence supporting the diagnosis of subacute granulomatous thyroiditis.

While serum thyroid hormone levels can indicate changes in thyroid function and a radionuclide scan could show patterns of thyroid uptake, they do not provide the histological evidence needed to confirm the diagnosis. A CT scan of the neck may provide images of the thyroid and surrounding structures, but it cannot identify the cellular components that establish the diagnosis. Thus, fine needle aspiration is uniquely suited for the confirmation of subacute granulomatous thyroiditis through direct cellular analysis.