raised TSH, normal free thyroid hormones
Last reviewed 04/2022
The large majority of patient with raised TSH and normal free thyroid hormones are suffering from subclinical autoimmune hypothyroidism.
These results occur more rarely in the following circumstances:
- the presence of heterophile antibodies
- mouse antibodies are used in many TSH assays
- patients may have antibodies to mouse immunoglobulins
- heterphile antibodies result in a false TSH elevation
- alternative assays should be used for these patients
- in patients taking a regular dose of thyroxine an increase in the TSH concentration may indicate thyroxine malabsorption, due to:
- small bowel disease
- cholestyramine
- iron therapy
- amiodarone therapy
- recovery from severe non-thyroidal disease
- congenital abnormalities of thyroid function:
- some cases of Pendred's syndrome