A method for the direct estimation of total serum thyroxine

  • P. P. A. Smyth
  • D. K. O’Donovan


Serum is deprotenized using 95% ethanol. The T4 thus released from the protein binding is quantitated by its competition with a fixed amount of T4123I for binding sites on a fixed amount of TBG. The mean value for thyroxine iodine in a group of 72 clinically euthyroid subjects is 5.94±1.34 g/100mls. giving a normal range of 3.3–8.6 μg/100mls. Agreement with the elinical status in a group of 130 subjects under assessment is 96.2%.

As well as providing a direct measurement of circulating thyroxine the method is not affected by the contaminants which invalidate the P.B.I. estimation.


  1. 1.
    Murphy, B. E. P. and Pattee, C. J. (1964).J. Clin. Endocr., 24: 187.PubMedCrossRefGoogle Scholar
  2. 2.
    Murphy, B. E. P. (1965).J. Lab. & Clin. Med., 66: 161.Google Scholar
  3. 3.
    Hansen, H. H. (1966).Scand. J. Clin. & Lab. Invest., 18: 240.CrossRefGoogle Scholar
  4. 4.
    Murphy, B. E. P., Pattee, C. J. and Gold, A. J. (1966).Clin. Endocr., 26: 247.CrossRefGoogle Scholar
  5. 5.
    Nakajima, H., Kuramochi, T. H. and Kubo, S. (1966).J. Clin. Endocr., 26: 99.PubMedCrossRefGoogle Scholar
  6. 6.
    Sterling, K. (1964).Mayo Clinic Proc., 37: 586.Google Scholar
  7. 7.
    Mason, C. C. and Shepherd, H. G. (1960).Amer. J. Clin. Path., 34: 40.Google Scholar
  8. 8.
    McDonnell, H. and Hingerty, D. (1967).Ir. J. Med. Sci., 6: 437.CrossRefGoogle Scholar
  9. 9.
    Clark, F. and Horn, D. B. (1965).J. Clin. Endocr., 25: 39.PubMedCrossRefGoogle Scholar

Copyright information

© Springer 1968

Authors and Affiliations

  • P. P. A. Smyth
    • 1
  • D. K. O’Donovan
    • 1
  1. 1.Department of Medicine and TherapeuticsUniversity CollegeDublin

Personalised recommendations