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

1974 ◽  
Vol 27 (5) ◽  
pp. 372-376 ◽  
Author(s):  
T K Bell ◽  
D A Boyle ◽  
D A Montgomery ◽  
S J Todd
Keyword(s):  
Thyroid Function ◽  
Free Thyroxine ◽  
Serum Thyroxine ◽  
Free Thyroxine Index

Thyroid Function in Respiratory Distress Syndrome (RDS) of the Newborn

PEDIATRICS ◽  
1974 ◽  
Vol 54 (4) ◽  
pp. 423-428
Author(s):  
Ralph A. Redding ◽  
Celina Pereira
Keyword(s):  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Thyroid Function ◽  
Gestational Age ◽  
Distress Syndrome ◽  
Newborn Infants ◽  
Free Thyroxine ◽  
Total Serum ◽  
Serum Thyroxine ◽  
Free Thyroxine Index

Preliminary evaluation of thyroid function, utilizing total serum thyroxine (T4) and triiodothyronine (T3) resin uptake, was assessed following delivery in three groups of babies and their respective mothers; 40 premature new-borns with respiratory distress syndrome (RDS), 39 prematures comparable by gestational age who failed to develop RDS, and 22 full-term normal babies. The group of premature newborn infants in whom RDS occurred, as compared to the other two groups, had significantly lower mean total serum thyroxine levels and "free thyroxine index" (T4 x %T3 uptake/100). When matched by gestational age, the differences were also significant. Two days following delivery, the total serum T4 in the surviving prematures with RDS as compared to prematures without RDS was also significantly lower. The mean values for total T4 and "free thyroxine index" in the respective mothers of the three groups were not significantly different. Since L-thyroxine has been shown to increase the production of lung surfactant, widely accepted as deficient in RDS newborn infants, an association between lung immaturity and fetal thyroid function is postulated.

A Comparison of Serum Thyroxine [T4(D)], RT3U Ratio and T4-RT3 Index with Radioiodine Uptake in the Triiodothyronine Suppression Test

1972 ◽  
Vol 11 (04) ◽  
pp. 317-323
Author(s):  
R. Höschl ◽  
T. M. D. Gimlette
Keyword(s):  
Free Thyroxine ◽  
Radioiodine Uptake ◽  
Serum Thyroxine ◽  
Before And After ◽  
Free Thyroxine Index ◽  
Suppression Test

SummaryA total of 132 triiodothyronine suppression tests were performed using 100 μg of T3 for 7 days. Radioiodine uptake at four hours, serum thyroxine [T4(D)], T3 binding coefficient [RT3U ratio] and free thyroxine index [T4-RT3 index] were estimated before and after a course of triiodothyronine.T4(D) decreased significantly in only 38.4% of T3 suppression tests assessed as positive by the decrease in radioiodine uptake; it did not change or increased significantly in 84.7% of tests negative by radioiodine uptake.RT3U ratio showed little change in all groups. The changes in T4-RT3 index were similar to those of T4(D).The correlation of changes in T4(D) with 4 hour radioiodine uptake is poor (r = 0.34).Agreement between changes in radioiodine uptake and T4(D) was observed only in 54% of tests; between changes in uptake and T4-RT3 index in 69.4%.Estimation of serum thyroxine or free thyroxine index in the T3 suppression test cannot substitute for the radioiodine uptake for reasons which are discussed.

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.

A Comparison of Serum Thyroxine [T4(D)], RT3U Ratio and T4-RT3 Index with Radioiodine Uptake in the TSH Stimulation Test

1972 ◽  
Vol 11 (04) ◽  
pp. 324-332
Author(s):  
R. Höschl ◽  
T. M. D. Gimlette
Keyword(s):  
Free Thyroxine ◽  
Stimulation Test ◽  
Radioiodine Uptake ◽  
Serum Thyroxine ◽  
Positive Serum ◽  
Free Thyroxine Index ◽  
Reliable Parameter ◽  
Stimulation Tests ◽  
Tsh Stimulation ◽  
Better Than

SummaryA total of 236 TSH stimulation tests were performed using 10 units of TSH intramuscularly. 4 hour uptake of 132I, serum thyroxine [T4(D)], T3 binding coefficient [RT3U ratio] and free thyroxine index [T4-RT3 index] were estimated before and 18 hours after TSH.In 88 tests classified by radioiodine uptake change as positive serum thyroxine increased significantly in only 63.7%, T4-RT3 index in 61.5%.Out of 108 tests classified as negative by radioiodine uptake, serum thyroxine increased significantly in 14.8% and T4-RT3 index in 13.0%.The RT3U ratio procedure used was the least reliable parameter in testing thyroid response to TSH stimulation, T4RT3 index was no better than T4(D) alone.The change in serum thyroxine levels in response to TSH stimulation is in our opinion unreliable for the evaluation of TSH tests, and correlates poorly with changes in radioiodine uptake (r = 0.37), for reasons which are discussed.

A Comparison of Free Thyroxine Concentration and the Free Thyroxine Index as Diagnostic Tests of Thyroid Function

1981 ◽  
Vol 18 (2) ◽  
pp. 88-92 ◽  
Author(s):  
J W Tuttlebee ◽  
R Bird
Keyword(s):  
Clinical Diagnosis ◽  
Thyroid Function ◽  
Diagnostic Tests ◽  
Oral Contraception ◽  
Free Thyroxine ◽  
Thyroid Status ◽  
Serum Free ◽  
Free Thyroxine Index ◽  
Diagnostic Index ◽  
In Pregnancy

Serum free thyroxine concentrations, measured by the Immo Phase kit, and free thyroxine index values were compared in 200 subjects classified according to age, sex, and clinical diagnosis. The free thyroxine concentration was as good as the free thyroxine index in hyperthyroid, hypothyroid, elderly, and acutely ill patients and a better diagnostic index of thyroid status in pregnancy and in oral contraception.

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