From the Guidelines
Elevated Anti-Thyroglobulin (Anti-Tg) antibody levels are a significant indicator of autoimmune thyroid disease, which is the most common autoimmune disorder associated with diabetes, occurring in 17-30% of patients with type 1 diabetes 1.
Key Points
- The presence of thyroid autoantibodies, including Anti-Tg, identifies patients at increased risk for thyroid autoimmunity 1.
- Anti-Thyroid Peroxidase (Anti-TPO) antibodies are more predictive of thyroid dysfunction than Anti-Tg antibodies in multivariate analysis 1.
- Elevated Anti-Tg antibody levels are predictive of thyroid dysfunction, most commonly hypothyroidism, although hyperthyroidism can also occur 1.
- Thyroid function tests may be misleading if performed at the time of diagnosis due to the effect of previous hyperglycemia, ketosis, or ketoacidosis, and should be repeated after a period of metabolic stability and good glycemic control 1.
- Patients with elevated Anti-Tg antibody levels should be monitored for thyroid dysfunction and treated accordingly, with thyroid hormone replacement therapy for hypothyroidism and comprehensive evaluation and treatment for hyperthyroidism 1.
From the Research
Significance of Elevated Anti-Thyroglobulin (Anti-Tg) Antibody Levels
Elevated Anti-Thyroglobulin (Anti-Tg) antibody levels have been associated with various clinical implications, including:
- Interference with thyroglobulin (Tg) measurement, leading to false-positive or false-negative results 2
- Increased risk of lymph node metastasis and cancer persistence/recurrence in patients with differentiated thyroid cancer (DTC) 3
- Association with symptom burden in patients with Hashimoto's thyroiditis, including fragile hair, face edema, edema of the eyes, and harsh voice 4
- Utility in diagnosing autoimmune thyroid disease (AITD), such as Hashimoto's thyroiditis and Graves' disease 5
- Potential use as a prognostic marker for DTC, with persistent/increasing TgAb levels indicating a higher risk of cancer persistence/recurrence and cancer mortality 3
Clinical Implications
The clinical implications of elevated Anti-Tg antibody levels include:
- Difficulty in monitoring differentiated thyroid cancer progression and recurrence due to interference with Tg measurement 2
- Association with increased symptom burden in patients with Hashimoto's thyroiditis 4
- Potential for false-positive or false-negative Tg results, leading to unnecessary imaging work-up or delayed diagnosis of cancer recurrence 2
- Utility in predicting post-partum thyroid dysfunction and thyroid dysfunction after interferon treatment 5
Diagnostic and Prognostic Value
The diagnostic and prognostic value of Anti-Tg antibody levels includes:
- Association with increased risk of cancer persistence/recurrence and cancer mortality in patients with DTC 3
- Potential use as a prognostic marker for DTC, with persistent/increasing TgAb levels indicating a higher risk of compromised prognosis 3
- Utility in diagnosing AITD, such as Hashimoto's thyroiditis and Graves' disease 5
- Association with symptom burden in patients with Hashimoto's thyroiditis, suggesting a role of thyroid autoimmunity in clinical manifestations of the disease 4