Thyroid function tests in acutely ill patients. comparison of analogue based free thyroid hormone assays with free thyroxine index

Pathology ◽  
1986 ◽  
Vol 18 (1) ◽  
pp. 94-97
Author(s):  
Russell R. Cooke ◽  
R. Pratt
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Thyroid Hormone ◽  
Function Tests ◽  
Free Thyroxine Index

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.

THYROID FUNCTION TESTS DURING PREGNANCY, THE NORMAL MENSTRUAL CYCLE AND IN WOMEN USING ORAL CONTRACEPTIVES

1969 ◽  
Vol 43 (2) ◽  
pp. 217-224 ◽  
Author(s):  
RUTH M. STANDEVEN
Keyword(s):  
Menstrual Cycle ◽  
Thyroid Function ◽  
Oral Contraceptives ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Clinical Use ◽  
Thyroid Status ◽  
Function Tests ◽  
Free Thyroxine Index ◽  
Normal Menstrual Cycle

SUMMARY Endogenous and exogenous oestrogenic effects on thyroid function tests were studied. [125I]Tri-iodothyronine charcoal uptake (T3 uptake) and protein-bound iodine (PBI) were measured in serum obtained from women during the menstrual cycle and the different trimesters of pregnancy and from women taking oral contraceptives for varying periods of time. The free thyroxine index (FTI) was calculated for the pregnant subjects and the free thyroxine factor (FTF) evaluated for all samples studied. Significant deviations from control values in T3 uptake, PBI, FTI and FTF could not be correlated with relatively large changes in the levels of oestrogens. T3 uptake results appeared to reflect changing oestrogenic patterns more closely than the corresponding PBI measurements. Evidence presented suggests that the FTF is preferred to the FTI for clinical use in the diagnosis of thyroid status although further modification to the FTF formula involving PBI and [125I]T3 charcoal uptake measurements may be necessary.

Thyroid Function Tests in Thyroxine-Binding Globulin Deficiency

1979 ◽  
Vol 16 (1-6) ◽  
pp. 313-314 ◽  
Author(s):  
C. F. Cusick
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Reference Range ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Thyroid Status ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Function Tests ◽  
Lowered Serum

Results are presented on two patients with complete and two with partial thyroxinebinding globulin (TBG) deficiency. All four subjects had lowered serum thyroxine but were clinically euthyroid. While thyroid hormone uptake tests or TBG assay were effective in the recognition of such individuals, indices based on these tests were misleading in assessing their thyroid status. Results within the reference range were obtained with the Immophase Free Thyroxine assay.

scholarly journals DIAGNOSTIC DILEMMA IN DISCORDANT THYROID FUNCTION TESTS DUE TO THYROID HORMONE AUTOANTIBODIES

2017 ◽  
Vol 3 (1) ◽  
pp. e22-e25 ◽  
Author(s):  
Panudda Srichomkwun ◽  
Neal H. Scherberg ◽  
Jasminka Jakšić ◽  
Samuel Refetoff
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Thyroid Function Tests ◽  
Diagnostic Dilemma ◽  
Thyroid Hormone Autoantibodies ◽  
Function Tests

Subclinical hypothyroidism

2011 ◽  
pp. 543-547
Author(s):  
Jayne A. Franklyn
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Expert Panel ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests ◽  
Serum Tsh

Subclinical hypothyroidism is defined biochemically as the association of a raised serum thyroid-stimulating hormone (TSH) concentration with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The term subclinical hypothyroidism implies that patients should be asymptomatic, although symptoms are difficult to assess, especially in patients in whom thyroid function tests have been checked because of nonspecific complaints such as tiredness. An expert panel has recently classified individuals with subclinical hypothyroidism into two groups (1): (1) those with mildly elevated serum TSH (typically TSH in the range 4.5–10.0 mU/l) and (2) those with more marked TSH elevation (serum TSH >10.0 mU/l).

Free thyroid hormone index, thyroid hormone/thyroxin-binding globulin ratio, triiodothyronine uptake, and thyroxin-binding globulin compared for diagnostic value regarding thyroid function.

1983 ◽  
Vol 29 (1) ◽  
pp. 74-79 ◽  
Author(s):  
T J Wilke
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Diagnostic Value ◽  
Clinical Findings ◽  
Thyroid Function Tests ◽  
Free Thyroid Hormone ◽  
Age Related ◽  
Age Dependent ◽  
Uptake Test ◽  
The Relationship

Abstract The thyroid hormone/thyroxin-binding globulin (TBG) ratio and the free thyroid hormone index (FTI) were compared in 372 subjects classified according to age, sex, and biochemical and clinical findings. Age-related variations in thyroid function tests were investigated, as was the relationship between triiodothyronine uptake and TBG. Men, but not women, showed significant age-dependent changes in concentrations of thyroid hormones. FTI was as good as the thyroid hormone/TBG ratio in hyperthyroidism and was a better index of thyroid status in pregnancy, TBG deficiency, and hypothyroidism. In addition, the triiodothyronine uptake correlated extremely well with TBG (r = -0.95, p less than 0.001) and was very efficient in detecting decreased and significantly increased concentrations of TBG. I conclude that FTI is a better discriminator of functional status of the thyroid over a wider range of TBG values than is the thyroid hormone/TBG ratio. Further, the triiodothyronine uptake test produced diagnostic information equivalent to that of TBG estimation and thus should not be replaced in routine use.

scholarly journals Report of the IFCC Working Group for Standardization of Thyroid Function Tests; Part 2: Free Thyroxine and Free Triiodothyronine

2010 ◽  
Vol 56 (6) ◽  
pp. 912-920 ◽  
Author(s):  
L. M. Thienpont ◽  
K. Van Uytfanghe ◽  
G. Beastall ◽  
J. D. Faix ◽  
T. Ieiri ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Working Group ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests

scholarly journals L-T4 Therapy in the Presence of Pharmacological Interferents

2020 ◽  
Vol 11 ◽  
Author(s):  
Salvatore Benvenga
Keyword(s):  
Thyroid Function ◽  
Cardiovascular Complications ◽  
Primary Hypothyroidism ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Function Tests ◽  
Frequent Monitoring ◽  
Serum Free Thyroxine

Pharmacological interference on L-thyroxine (L-T4) therapy can be exerted at several levels, namely from the hypothalamus/pituitary through the intestine, where the absorption of exogenous L-T4 takes place. A number of medications interfere with L-T4 therapy, some of them also being the cause of hypothyroidism. The clinician should be aware that some medications simply affect thyroid function tests with no need of modifying the dose of L-T4 that the patient was taking prior to their prescription. Usually, the topic of pharmacological interference on L-T4 therapy addresses the patient with primary hypothyroidism, in whom periodic measurement of serum thyrotropin (TSH) is the biochemical target. However, this minireview also addresses the patient with central hypothyroidism, in whom the biochemical target is serum free thyroxine (FT4). This minireview also addresses two additional topics. One is the costs associated with frequent monitoring of the biochemical target when L-T4 is taken simultaneously with the interfering drug. The second topic is the issue of metabolic/cardiovascular complications associated with undertreated hypothyroidism.

scholarly journals HYPOTHYROIDISM AND GOITER IN A YOUNG MALE WITH SUSPECTED DIETARY IODINE DEFICIENCY FOLLOWED BY THYROTOXICOSIS AFTER IODINE SUPPLEMENTATION

2020 ◽  
Vol 6 (1) ◽  
pp. e19-e22
Author(s):  
Itivrita Goyal ◽  
Manu Raj Pandey ◽  
Rajeev Sharma
Keyword(s):  
Thyroid Gland ◽  
Thyroid Function ◽  
Iodine Deficiency ◽  
Urinary Iodine ◽  
Young Male ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Normal Range ◽  
Iodine Supplementation ◽  
Function Tests

Objective: Iodine deficiency disorders (IDDs) remain a major public health concern in most parts of the world but are extremely rare in North America. We describe a case of goiter in a young male with dietary history and findings suggestive of IDD. Methods: Laboratory and imaging procedures including thyroid function tests, autoantibodies, urine iodine, thyroid ultrasound, and radioactive iodine (RAI) uptake scan were performed. Results: On initial presentation, thyroid-stimulating hormone (TSH) was 24.4 mIU/L (normal range is 0.4 to 5.0 mIU/L), free thyroxine was <0.4 ng/dL (normal range is 0.8 to 1.8 ng/dL), and thyroid peroxidase antibody was positive at 43 IU/mL (normal range is <35 IU/mL). He reported consuming strawberries and peanut butter sandwiches with no intake of dairy or seafood due to gastrointestinal issues (abdominal pain, bloating, and nausea). Physical exam revealed a diffusely enlarged, palpable thyroid gland (grade II goiter). Ultrasound of the neck showed an enlarged thyroid gland with no nodules. RAI uptake scan showed diffuse increased uptake (91%). Given his poor diet, a 24-hour urinary iodine excretion test was ordered which was suggestive of very low iodine intake. He was started on multivitamins with 150 μg of iodine daily. On follow up, clinical exam showed grade I goiter and TSH had normalized to 0.7 mIU/L and free thyroxine was 1.2 ng/dL. He continued on iodine supplementation and tolerated iodine-rich foods. Six months later, thyroid function tests showed hyperthyroidism with TSH of <0.002 ng/dL and free thyroxine was elevated to 2.8 ng/dL. Iodine supplements were stopped. Conclusion: Hypothyroidism and goiter due to IDD should be suspected in the setting of poor dietary intake. IDDs can be rapidly diagnosed in a patient on a restricted diet with multiple urinary iodine determinations and RAI study. Regular thyroid labs should be done to monitor for hyperthyroidism that can develop after iodine supplementation.

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