Interpretation

Increased in:

  • Primary Hypothyroidism
  • Mild increase in subclinical hypothyroidism, which is defined as a mild increase in serum TSH and normal free thyroxine and triiodothyronine levels
  • Hashimoto's thyroiditis patients who are euthyroid
  • Ectopic TSH secretion in certain cancers (lung, breast).
  • Recovery phase of subacute thyroiditis
  • Recovery phase of a non-thyroidal illness
  • Thyroid hormone resistance

Decreased in:

  • Primary Hyperthyroidism
  • Secondary (pituitary) hypothyroidism
  • Tertiary hypothyroidism
  • Graves disease
  • Thyroiditis
  • Toxic adenomas
  • Acute medical or surgical illness
  • Some drugs such as dopamine
  • High-dose corticosteroids
  • Mild decrease in subclinical hyperthyroidism (mild decrease in serum TSH and normal free thyroxine and triiodothyronine levels, as in treated Graves disease, toxic multinodular goiter, autonomous thyroid hormone secretion, exogenous thyroid hormone therapy)
  • Euthyroid sick syndrome