Diagnosis is usually suspected when the thyroid suddenly becomes swollen, tender (painful on pressure) and painful especially if associated with hyperthyroidism.

  1. Thyroid function test
  2. Other blood test
  3. Fine needle aspiration biopsy shows characteristic giant multinucleated cells in the aspirated material microscopically.
    • Diagnosis is confirmed by low radioactive iodine uptake (thus distinguishing Subacute thyroiditis from Grave’s disease) and increased T3 and T4.
    • ESR (Erythrocyte sedimentation rate) is markedly elevated.
    • Antithyroid antibodies are low (distinguishing Subacute thyroiditis from Hashimoto’s thyroiditis)