During primary hypothyroidism, where a defect in the thryoid gland is producing low levels of T3 and T4, the TSH level is increased. TSH is released in elevated quantities in an attempt to stimulate the thryoid to produce more T3 and T4 as part of a feedback mechanism.
Serum TSH levels five-times the upper limit of normal in the presence of a low T4 and low T3 uptake could mean which of the following:
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