- Negative result: A negative TRAb result means that no detectable antibodies against the TSH receptor were found in the blood. This suggests the absence of TSH receptor autoantibodies associated with autoimmune thyroid diseases such as Graves' disease. However, it's important to note that a negative result does not rule out the possibility of thyroid disorders or other causes of thyroid dysfunction.
- Positive result: A positive TRAb result indicates the presence of TSH receptor autoantibodies in the blood. This suggests the possibility of an autoimmune thyroid disease, particularly Graves' disease. Positive TRAb results are further categorized based on the type of antibodies detected:
- Thyroid-stimulating antibodies (TSAb): TSAb are TRAb that mimic the action of TSH on the TSH receptor, leading to excessive production of thyroid hormones. High levels of TSAb are associated with hyperthyroidism and are often seen in individuals with Graves' disease.
- Thyroid-blocking antibodies (TBAb): TBAb are TRAb that block the binding of TSH to the TSH receptor, inhibiting the normal stimulation of the thyroid gland. Low or absent levels of TBAb suggest a lack of inhibition on the TSH receptor, which can contribute to hyperthyroidism in some cases.
The interpretation of TRAb test results should be done in conjunction with other thyroid function tests, such as TSH, T4, and T3 levels, as well as clinical evaluation and symptoms. These additional tests provide a more comprehensive assessment of thyroid function and help guide the diagnosis and treatment decisions.