Research Article

Are biochemical tests of thyroid function of any value in monitoring patients receiving thyroxine replacement?

Br Med J (Clin Res Ed) 1986; 293 doi: https://doi.org/10.1136/bmj.293.6550.808 (Published 27 September 1986) Cite this as: Br Med J (Clin Res Ed) 1986;293:808
  1. W D Fraser,
  2. E M Biggart,
  3. D S O'Reilly,
  4. H W Gray,
  5. J H McKillop,
  6. J A Thomson

    Abstract

    To establish their role in monitoring patients receiving thyroxine replacement biochemical tests of thyroid function were performed in 148 hypothyroid patients studied prospectively. Measurements of serum concentrations of total thyroxine, analogue free thyroxine, total triiodothyronine, analogue free triiodothyronine, and thyroid stimulating hormone, made with a sensitive immunoradiometric assay, did not, except in patients with gross abnormalities, distinguish euthyroid patients from those who were receiving inadequate or excessive replacement. These measurements are therefore of little, if any, value in monitoring patients receiving thyroxine replacement. To stop doing thyroid function tests in these cases would result in considerable savings nationally in the cost of reagents in laboratories using commercial kits.