T3 Reverse – $49

Reverse T ₃ (rT ₃) has limited application. The assay may be useful in the diagnosis of nonthyroidal illness (NTI). Patients with NTI have low T ₃ concentrations and increased concentrations of rT ₃. RT ₃ may be useful in neonates to distinguish euthyroid sick syndrome from central hypothyroidism