Figure 13. TgAb Trends in Response to Treatment. Typical trends in TgAb following thyroidectomy in patients rendered disease-free by thyroidectomy (pattern A) versus patents with persistent/recurrent disease (pattern B). TgAb levels may rise or become detectable de novo in response to an increase in Tg antigen following surgical injury, lymph node recurrence(s), lymph node resection(s), FNA biopsy of metastatic lymph nodes or radioiodine therapy.