Autoimmune thyroiditis

This code represents an inflammatory condition of the thyroid gland caused by an autoimmune response, where the body's immune system mistakenly attacks its own thyroid tissue. This often leads to hypothyroidism due to the gradual destruction of thyroid cells.

Use this code when documentation explicitly states "autoimmune thyroiditis," "Hashimoto's thyroiditis," or "chronic lymphocytic thyroiditis." This diagnosis is typically supported by laboratory findings such as elevated thyroid-stimulating hormone (TSH), low free T4, and the presence of thyroid autoantibodies (e.g., anti-TPO, anti-thyroglobulin).

• Do not confuse with other forms of thyroiditis (e.g., subacute, acute, drug-induced) which have distinct codes.
• Code any associated hypothyroidism separately, typically as an additional diagnosis, if documented.
• Ensure the documentation clearly specifies the autoimmune nature of the thyroiditis to support this specific code.