TSH Receptor Antibody (TRaB)
                                             Produced by: Thyroid Infiltrating Lymphocytes
Definition / Purpose: Thyroid stimulating hormone receptor antibodies include two types of auto-antibodies that attach to proteins in the thyroid to which TSH normally binds (TSH receptors):
1. Thyroid stimulating immunoglobulin (TSI) binds to receptors and promotes the production of thyroid hormones, leading to hyperthyroidism.
2. Thyroid binding inhibitory immunoglobulin (TBII) blocks TSH from binding to receptors, blocking production of thyroid hormones and resulting in hypothyroidism.

Lab Reference Range: ≤16% Inhibition
When to order:

• When ruling out the diagnosis of Graves or Hashimotos

Pearls:
Half-life: 90-125 days