Evaluation of Thyopac-3 Test in the In-vitro Assessment of Thyroid Function

Clark, F.; Brown, Hazel

doi:10.1136/bmj.1.5698.713

Cited by 41 publications

(12 citation statements)

References 10 publications

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“…This is a distinct advantage in a busy laboratory, especially when the assay is being done by relatively inex-33 0 34 perienced personnel. Similar findings on the time dependence of the Thyopac test have been made by Clark and Brown (1970a). We have also found that the technique is less influenced by the temperature of incubation, and no correction is necessary for normal variations in laboratory temperature.…”

Section: Discussionsupporting

confidence: 87%

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

Chan¹,

McAlister²,

Landon³

1972

J Clin Pathol

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(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

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Section: Discussionsupporting

confidence: 87%

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

Chan¹,

McAlister²,

Landon³

1972

J Clin Pathol

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“…In the majority of pregnant women and in the TBG-deficient subject, the values for Thyopac-3 and -4 differed by more than 2 standard deviations from the mean normal value, corroborating previous observations (Clark and Brown, 1970a). …”

Section: Resultssupporting

confidence: 90%

Conventional and dual competitive binding analyses of thyroxine using the Thyopac-4 kit

Hamada¹,

Torizuka²,

Uete³

1974

J Clin Pathol

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sYNoPsis A simple method is described for the simultaneous determinations of thyroxine and the effective thyroxine ratio (ETR) using a single kit of Thyopac-4. Thyopac ETR values obtained were 1-00 ± 0'03 for normal subjects; 1 22 ± 0 11 for hyperthyroid; 0-87 ± 0-04 for hypothyroid; and 1 02 ± 0'05 for pregnant women. Cases with TBG deficiency and the nephrotic syndrome indicated normal values. The value (x) was correlated significantly (y = + 0-961) with the free Thyopac index (y), representing a regression equation of y = 71*7x2 -88-4x + 24x2. Thyopac ETR was shown to be useful in differentiating normal thyroid states from abnormal, irrespective of changes in T4-binding globulin (TBG). Further, the T4 value obtained simultaneously made it possible to detect changes in the TBG level by noting an inconsistent value for the effective thyroxine ratio.It is known that free thyroxine (T4) in serum enters peripheral cells directly related to hormonal action, and therefore that its concentration is the best indicator of thyroid status (Robbins and Rall, 1960). However, equilibrium dialysis or ultrafiltration to measure free T4 is so laborious that various kinds of free T4 indices were devised to be calculated from the T4 value and triiodothyronine (T3) resin uptake (Clark and Horn, 1965;Goolden, Gartside, and Sanderson, 1967;Hamada, Nakagawa, Mori, and Torizuka, 1970). Further, dual competitive binding analyses such as the effective thyroxine ratio (ETR) (Mincey, Thorson, Brown, Morrison, and McIntosh, 1971) and the normalized serum thyroxine (T4N) (Ashkar and Bezjian, 1972) have recently been introduced as other indicators of free T4 level.The present paper describes a simple method for simultaneous determinations of serum T4 and Thyopac ETR2 by a single kit of Thyopac-4. Laboratory tests of thyroid status have provided corroboration for the validity of the present method."This paper was presented in part at the annual meeting of the Japan Endocrinological Society, April 9-11, 1973. 'Res-O-Mat effective thyroxine ratio is a trademark of Mallinckrodt Chem. Works. The dual competitive binding analysis using a Thyopac-4 kit was called tentatively Thyopac ETR.Received for publication 3 January 1974.Materials and Methods Sera were tested from 86 patients in the Central Radioisotope Division of Kyoto University Hospital and the Division of Clinical Biochemistry and Obstetric Clinic of Kitano Hospital. Forty were euthyroid subjects, 18 were patients with hyperthyroidism, 14were patientswith primaryhypothyroidism, 12 were pregnant women in the second and third trimesters, one was a patient with congenital TBG deficiency, and one with the nephrotic syndrome.

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“…The following thyroid function tests were carried out: thyroidal radioiodine uptake and scan, serum thyroxine (Murphy, 1965), T} resin uptake (Clark and Brown, 1970), serum triiodothyronine (Mitsuma et al. 1971) and thyroid-stimulating hormone (TSH) (Hall el at, 1971).…”

Section: Methodsmentioning

confidence: 99%