scholarly journals Evaluation of new kits for the assessment in vitro of thyroid function by determination of serum total thyroxine, free TBG capacity, and free thyroxine index using Sephadex G-25 and 125I-labelled triiodothyronine and thyroxine

1974 ◽  
Vol 27 (2) ◽  
pp. 153-161 ◽  
Author(s):  
P. J. N. Howorth ◽  
C. G. McKerron
Keyword(s):  
Thyroid Function ◽  
Free Thyroxine ◽  
Free Thyroxine Index ◽  
Total Thyroxine

Pictorial reporting of multiple thyroid function results.

1976 ◽  
Vol 22 (10) ◽  
pp. 1562-1566
Author(s):  
R W Pain ◽  
B M Duncan
Keyword(s):  
Thyroid Function ◽  
Reporting System ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Testing Procedures ◽  
Function Tests ◽  
Free Thyroxine Index ◽  
Total Thyroxine ◽  
Experience Difficulty

Abstract Clinicians experience difficulty in correctly interpreting the results of in vitro thyroid function tests in the presence of abnormalities of thyrobinding proteins or when results are borderline. This difficulty has been largely resolved in our laboratory by three innovations. First, the borderline areas for each of three routine tests of thyroid function (total thyroxine, thyrobinding index, and free thyroxine index) were accurately determined. Second, the results from this routine profile of three tests were displayed pictorially so as to produce patterns characteristic of various diagnostic situations, including euthyroidism in the presence of abnormalities of thyrobinding proteins. Third, interpretive comments and, in the case of borderline patterns, suggested further testing procedures were added to the report. Clinicians find the reporting system helpful and respond when additional tests are suggested. The system, operated manually at first, was later computerized.

Simple modifications of three routine in vitro tests of thyroid function.

1976 ◽  
Vol 22 (10) ◽  
pp. 1715-1718 ◽  
Author(s):  
R W Pain
Keyword(s):  
Diagnostic Accuracy ◽  
Thyroid Function ◽  
False Positive ◽  
Reference Range ◽  
False Negative ◽  
Work Load ◽  
In Vitro Tests ◽  
Free Thyroxine Index ◽  
Total Thyroxine

Abstract Semi-automation of equipment and simple modifications of technique reduced the work load without loss of diagnostic accuracy for three commonly used in vitro tests of thyroid function (total thyroxine, thyrobinding index, and free thyroxine index). Major innovations were the use of serum standards for all tests and having each duplicate for tests performed by a different technician. Attention is drawn to the false-positive and false-negative errors that occur when the 95% euthyroid limits is the sole reference range used.

EVALUATION OF THYROID STATUS WITH THE "EFFECTIVE THYROXINE RATIO" (E. T. R.®)

1974 ◽  
Vol 77 (2) ◽  
pp. 250-256 ◽  
Author(s):  
Klaus Kølendorf ◽  
Kaj Siersbæk-Nielsen ◽  
Jens Mølholm Hansen ◽  
Thorkild Friis
Keyword(s):  
Thyroid Function ◽  
Thyroid Function Test ◽  
Free Thyroxine ◽  
Normal Range ◽  
High Positive Correlation ◽  
Function Test ◽  
Free Thyroxine Index ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients

ABSTRACT A new in vitro thyroid function test, "Effective Thyroxine Ratio" (ETR®) has been tested in 170 patients, and the ETR values in patients with normal and abnormal thyroid function have been compared to the concentration of absolute free thyroxine and free thyroxine index in serum. Among 42 hyperthyroid patients tested with ETR, 13 had values within normal range (30.9 per cent). Three of 18 hypothyroid patients had normal values (16.8 per cent). Eighty-nine per cent of 27 pregnant women and all of 17 patients treated with genuine oestrogens had ETR values within normal range. A high positive correlation was found between values of ETR, absolute free thyroxine in serum (r = 0.62) and free thyroxine index (r = 0.83).

DETERMINATION OF TOTAL AND FREE SERUM THYROXINE IN THYROID DISEASES

1971 ◽  
Vol 67 (4) ◽  
pp. 793-800 ◽  
Author(s):  
K. Liewendahl ◽  
J. Tötterman ◽  
B.-A. Lamberg
Keyword(s):  
Rapid Method ◽  
Clinical Laboratory ◽  
Normal Values ◽  
Free Thyroxine ◽  
Free Thyroxine Index ◽  
Total Thyroxine ◽  
Competitive Protein Binding ◽  
Free Serum ◽  
Good Linear Correlation

ABSTRACT The free thyroxine fraction in serum was determined by means of a rapid method based on the uptake of radioactive thyroxine by Sephadex (T4U). The corresponding values for percentage free thyroxine (PFT4) were obtained by simultaneous determination of the dialysable fraction. A good linear correlation was established between the two methods. Serum total thyroxine (T4) was determined by the competitive protein-binding technique. The concentration of the absolute free thyroxine (AFT4) was calculated. Of the three laboratory parameters tested, AFT4 showed the highest discrimination in both hyper- and hypothyroidism. The »free thyroxine index«, FT4I, which is a product of T4 and T4U, proved equally useful. Good results were also obtained with T4, whereas PFT4 showed the largest overlap with the normal values. PFT4 is important, however, for the calculation of AFT4. The rapid method for determination of the free thyroxine fraction described in this paper is suitable for routine use in the clinical laboratory.

Evaluation of a Kit (Thyrolute) for the Combined Determination of Serum Total Thyroxine and Sequential Free Thyroxine Index using Sephadex G-25 and 125I-thyroxine

1975 ◽  
Vol 12 (1-6) ◽  
pp. 200-206 ◽  
Author(s):  
P. J. N. Howorth ◽  
C. G. McKerron ◽  
P. Marsden
Keyword(s):  
Normal Subjects ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Status ◽  
Two Stage ◽  
Accuracy And Precision ◽  
Free Thyroxine Index ◽  
Total Thyroxine ◽  
Similar Accuracy

A new kit (Thyrolute, Ames) for the combined determination of serum total thyroxine (T-4) and sequential free thyroxine index (F.T.I.) using Sephadex G-25 and 125I-thyroxine was evaluated in 136 patients and normal subjects. The T-4 determination was virtually identical to that used in the Ames Tetralute kit and had a similar accuracy and precision. The sequential F.T.I. was compared with a two-stage F.T.I. The two F.T.I.s showed highly significant correlations in the various groups of patients except euthyroid women with raised thyroxine-binding globulin (TBG) (pregnant or oral contraceptive). The overlap found for the sequential F.T.I. between euthyroid, hypothyroid, and thyrotoxic patients was slightly inferior (9%) to that found with the two-stage F.T.I. (6%), but its diagnostic success rate was higher than that of the serum T-4 determination alone. Serial observations of serum T-4 and sequential F.T.I. were also made on eight patients receiving carbimazole therapy for hyperthyroidism. The sequential F.T.I. showed complete parallelism with serum T-4 regardless of thyroid status, so that it was of no practical value in these patients. It was concluded that the sequential F.T.I kit would be of most value in the smaller hospital laboratory lacking facilities for the radioimmunoassay of thyroid hormones and thyroid stimulating hormone.

Investigation of the Free and Total Thyroxine-binding Capacity of Plasma Proteins in Thyroid Disorders

1971 ◽  
Vol 10 (04) ◽  
pp. 299-304
Author(s):  
József Takó ◽  
János Fischer ◽  
Jusztina Juhász ◽  
Ilona Sztraka ◽  
István Kapus ◽  
...  
Keyword(s):  
Blood Cell ◽  
Thyroid Function ◽  
Oral Contraceptives ◽  
Red Blood Cell ◽  
Plasma Proteins ◽  
Binding Capacity ◽  
Thyroid Disorders ◽  
Thyroid Function Tests ◽  
Total Thyroxine

SummaryThe results of thyroid function tests have been compared with data on the thyroxine-binding capacity of plasma proteins in hyper-, hypo- and euthyroid cases, the latter including women taking oral contraceptives (Infecundin). It was found that there exists a significant correlation of exponential nature between the in vitro red blood cell 125I-triiodothyronine uptake (RCU) and the free thyroxine-binding capacity of the thyroxine-inding globulin (TBG).

scholarly journals Evaluation of free and total L-thyroxine in serum by a commercial procedure.

1981 ◽  
Vol 27 (1) ◽  
pp. 149-152 ◽  
Author(s):  
M J Obregon ◽  
A Kurtz ◽  
R Ekins ◽  
G Morreale de Escobar
Keyword(s):  
Pregnant Women ◽  
Plasma Proteins ◽  
Diagnostic Value ◽  
Free Thyroxine ◽  
Total Thyroxine ◽  
Dialysis Method ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients ◽  
Normal Controls

Abstract We assessed a commercial kit (Corning Medical) for "free" and total thyroxine determination, results being compared to those obtained by the Ekins and Ellis dialysis method (free thyroxine) and the method of Weeke and Orskov (total thyroxine). The kit procedure permits determination of both free and total thyroxine within 4 to 5 h, and the combined results may disclose changes in binding to plasma proteins that would be missed if only free thyroxine were determined. With both free-thyroxine methods, the values distinguished hyperthyroid patients from normal controls and pregnant women with 100% accuracy, but there was some overlap between hypothyroid patients and controls. Absolute values with the kit procedure often exceed those obtained by dialysis, especially for hypothyroid patients and pregnant women. We conclude that the kit may be of as much diagnostic value as the dialysis method if the limitations regarding absolute values are kept in mind and the test is not used as a substitute for thyrotropin determinations in cases of suspected hypothyroidism.

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