Evaluation of a New In-vitro Blood Test for Determining Thyroid Status: The Effective Thyroxine Ratio

Thorson, Stephen C.; Mincey, E.K.; McIntosh, H. W.; Morrison, Robert E.

doi:10.1136/bmj.2.5805.67

Cited by 43 publications

(4 citation statements)

References 12 publications

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“…It is 87% accurate in subjects with high TBG activities and 68% accurate in patients with low TBPA. However, Thorson et al (1972) found a 99% accuracy of the ETR estimation compared with 98% for free T4 index in patients with high levels of T,-binding proteins but expressed the results as percentages of values falling into the actual ranges of observed values. When the results are expressed in this way (Table 3) there is a 100% diagnostic accuracy of ETR compared with 79% for free T4 index in subjects with elevated TBG activities (Group 3).…”

Section: Discussionmentioning

confidence: 90%

“…The ETR overcomes most of the problems of the free T, index and Mincey and co-workers (Mincey et al, 1971Thorson et al, 1972) found it to have a high degree of 'specificity' in defining abnormal thyroid status, irrespective of the presence of T,-binding abnormalities, and a diagnostic accuracy of 99% in defining thyroid status in patients with T, binding abnormalities compared with a value of 98% found for free T4 index. In studies comparing ETR with an actual measurement of free T, concentration as well as free T, index, Wellby ef al.…”

Section: Introductionmentioning

confidence: 99%

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A Comparison of Effective Thyroxine Ratio, Free Thyroxine Index and Free Thyroxine Concentration in Correcting for Thyroxine‐binding Abnormalities in Serum

Wellby

O'Halloran

Marshall

1974

Clinical Endocrinology

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SUMMARY The effective thyroxine ratio (ETR), a single test of thyroid function which has a highly significant linear correlation with serum free thyroxine (T4) concentration, was assessed for its effectiveness in distinguishing the euthyroid state in subjects with abnormalities of T4‐binding proteins. In patients with low activity of T4‐binding proteins, the diagnostic accuracy of the ETR (80±5%) is superior to that of the free T4 index (62±5%) and free T4 concentration (67%). In patients with elevated T4‐binding proteins the diagnostic accuracy of ETR was even higher at 93±5% and again better than the free T4 index (83%) and the free T4 concentration (91%).

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Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

A Comparison of Effective Thyroxine Ratio, Free Thyroxine Index and Free Thyroxine Concentration in Correcting for Thyroxine‐binding Abnormalities in Serum

Wellby

O'Halloran

Marshall

1974

Clinical Endocrinology

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“…The results obtained in this screening experiment are in agreement with other recent ETR findings. Higher reliability values have been obtained in I studies of patients who had changes in serum protein pattern (9). The following facts, furthermore, seem to justify the introduction of ETR into routine use: the test is simple to perform, it is not sensitive to iodine contamination, and it yields reliable results despite variations in TBG (e.g.…”

Section: Discussionmentioning

confidence: 98%

The Value of the Effective Thyroxine Ratio Compared With Other Common Thyroid Tests

Timonen¹,

Haapalahti²,

Reinilä³

et al. 1974

Journal of Internal Medicine

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Absfract. The purpose of the present work was to compare the reliability of the new in vitro thyroid test, ETR, with that of the other commonly used thyroid tests in three different ways. 1. Comparison of the test results with the clinical picture obtained by a doctor on the basis of anamnesis and status. 2. Investigation of the correlation of ETR with the other thyroid tests. 3. Investigation of the ability of the tests to discriminate between states of hypo-, hyper-and euthyroidism. The material examined consisted of 62 patients. The results showed ETR to be the best of the laboratory tests according to all three criteria. ETR correlated with the clinical picture obtained on the basis of anamnesis and status in 9 5 % of the cases. ETR correlated highly significantly with the other thyroid tests used (T,, T, (= T, uptake), FT, index, PBI, cholesterol and radioiodine test). The discriminative capacity of ETR was highly significant in all the states, while the ability of the T, test to distinguish hypothyroidism was not s@tistically significant.Mincey et al. (6) described in 1972 a new type of in vitro thyroid test, ETR (the effective thyroxine ratio), which is technically simpler than the assay of free serum thyroxine (7) or the calculation of indices for it (1, 3, 4). ETR provides a reliable indication of the thyroid status and is independent of the variations in concentration of the serum protein binding thyroid hormone (9), which occur, e.g., during pregnancy and during the use of oral contraceptives. The ETR test assays simultaneously the serum total thyroxine and the thyroxine-binding capacity of thyroglobulin (TBG) (6). The result is expressed as a ratio to normal serum. It has been shown that ETR has a 99% diagnostic accuracy in determining the thyroid status of a material of patients consisting of eu-, hyper-and hypothyroid individuals, gravidae, and users of contraceptives (9).The purpose of the work was to compare the value of ETR with the other in vitro thyroid tests and the radioiodine test. MATERIAL AND METHODSThe material consisted of 62 patients, 36 of whom were euthyroid, 16 hyperthyroid and 10 hypothyroid. The thyroid status was clinically evident and the material included no patients with other diseases of the thyroid gland, no gravidae, and no users of contraceptives. From each patient 10 ml venous blood was drawn without anticoagulants and stored at + 4°C until analysed.ETR was assayed according to Mincey et al. by the Res-0-Mat@-ETR test (6). The method is a competetive protein binding assay, and a resin strip is used as the secondary binder. The results have been given as a ratio to normal serum, the normal values con'firmed by numerous investigations being 0.86-1.10. Between-assay variation was 5.2%. Thyroxine (T,) was assayed by the Res-0-Mat@-T, test ( 5 ) , and the results are here expressed as p n o l of thyroxine iodine/l. The normal values are 0 . 2 6 0.70 pmolll. T, uptake was measured by the Res-0-Mat@-T, test (7). The T, results were calculated in a manner inverse to the original m...

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“…The effective thyroxine ratio (ETR) (Thorson et al, 1972) is a one-stage form of free thyroxine index, which is available commercially in kit form and has been shown to be as good an index of hyperthyroidism as the FT41 (Toft et al, 1973a), although D'Haene et al (1974) found a poor correlation between the two tests and on statistical grounds preferred to use the FT4I derived from a two-stage procedure.…”

Section: T H E D I a G N O S I S O F Thyrotoxicosis Total Serum Thyromentioning

confidence: 99%

The Diagnosis and Treatment of Thyrotoxicosis

Irvine

Toft

1976

Clinical Endocrinology

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Evaluation of a New In-vitro Blood Test for Determining Thyroid Status: The Effective Thyroxine Ratio

Cited by 43 publications

References 12 publications

A Comparison of Effective Thyroxine Ratio, Free Thyroxine Index and Free Thyroxine Concentration in Correcting for Thyroxine‐binding Abnormalities in Serum

A Comparison of Effective Thyroxine Ratio, Free Thyroxine Index and Free Thyroxine Concentration in Correcting for Thyroxine‐binding Abnormalities in Serum

The Value of the Effective Thyroxine Ratio Compared With Other Common Thyroid Tests

The Diagnosis and Treatment of Thyrotoxicosis

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