Comparison of two triiodothyronine uptake techniques for the assessment of thyroid function

Abstract

(Goodhead and McAlister, 1970). Nonetheless, all these procedures have the disadvantage that they alter the equilibrium between bound and free hormone so that the percentage uptake increases with time. Furthermore, as the rate of dissociation is temperature dependent, both temperature and the duration of incubation must be rigidly standardized. Recently Amersham have introduced the Thyopac kit based on the use of a molecular sieve with a pore size such that only the free fraction can enter its matrices. This procedure has the advantage that the equilibrium of the reaction is not disturbed and, therefore, accurate timing of the period of incubation is unnecessary.The purpose of the present paper is to compare the simplicity, precision, and diagnostic value of the Triosorb and Thyopac T3 procedures. Materials and MethodsSera from 263 subjects were tested, of whom 114 were

An evaluation of absorbent granule kits for determining serum thyroxine concentration and free thyroxine index in the diagnosis of thyroid function.

“…The Thyopac-3 results obtained here gave a normal range of 95 to 122% which is similar to the 97 to 122 % range found by Chan et al (1972). When the Thyopac-4 results are used with the Thyopac-3 results to give values for TFTI, discrimination between different thyroid conditions is better than using the Thyopac-3 or Thyopac-4 kits alone.…”

“…Thyopac-3 kits have the advantage that the results are not time dependent compared with those of Triosorb kits (Chan et al, 1972). Watson and Lees (1973) have discussed the limitations of PBI estimations, including iodine contamination, compared with serum T4 estimations and have concluded that the serum PBI test is obsolete as a test of thyroid function.…”

“…They have also investigated a free thyroxine index calculated from the PBI and Thyopac-3 measurements (Clark and Brown, 1970b). Chan, McAlister, and Landon (1972) have compared the results from kits of Thyopac-3 and Triosorbl and investigated the free thyroxine index also calculated from the PBI values.…”

Assessment of a Simple Technique for the Determination of Serum Thyroxine

“…Specimens were counted in a y-counter for 100 s (minimum of 3 x 10 4 counts). This test has recently been evaluated (Chan, McAlister and Landon, 1972).…”

Hyperprolactinaemia and Microadenomas in Primary Hypothyroidism

“…Serum T4 was measured by radioimmunoassay (reagents from North East Thames Region Immunoassay Unit), THUT was measured using a modification of the 'Thyopac Three' method (Chan et al, 1972). TSH levels were assessed by an immunoradiometric assay as described by Newman et al (1985) except that a '"I labelled mouse monoclonal anti-TSH antibody was used in place of the affinity-purified, polyclonal, labelled sheep anti-TSH antibody.…”