Thyroid Disorders

Common Diagnostic Tests in Thyroid Disorders
Test Comments
Thyroid-stimulating hormone (TSH) Most sensitive test to detect 1° hypo- and hyperthyroidism.
Used as primary screening test for thyroid disease.
↓’d by dopamine, glucocorticoids, severe illness.
May not be accurate in central hypothyroidism.
Free T4 (fT4) Unbound T4, not influenced by TBG. Checked in a variety of thyroid states including hyperthyroidism & central hypothyroidism
Total T3 Total serum concentrations of T3 (liothyronine). Useful when evaluating for hyperthyroidism.
Antithyroid peroxidase Ab (anti-TPO) Antithyroid peroxidase (TPO) seen in s (high titer), painless subacute thyroiditis and Graves’ disease (low titer)