Long term changes in serum T4, T3, and TSH in benign thyroid disease

2004 ◽  
Vol 43 (05) ◽  
pp. 158-160 ◽  
Author(s):  
F. Hartmann ◽  
R. Rödel ◽  
M. Reinhardt ◽  
H.-J. Biersack
Keyword(s):  
Thyroid Function ◽  
Small Variation ◽  
Reference Ranges ◽  
Thyroid Function Tests ◽  
Free T4 ◽  
Wide Range ◽  
Serum T4 ◽  
The Individual ◽  
Benign Thyroid

Summary:Aim: The diagnosis of abnormalities of thyroid function is generally based on the measurement of thyroid hormones and TSH in blood. The recommended reference ranges for serum T4 and T3 as well as TSH are quite wide as the result of large differences in thyroid function tests in healthy persons. It has been proven that the individual variation within an individual is small, compared with the variation between individuals. We investigated long term variations of these parameters in patients with and without benign thyroid diseases. Methods: We performed long term follow-up serum determinations of T3, T4, and TSH in a total of 150 patients for a time period of 3 to 13 years. The majority of patients had been put on L-thyroxine. Values of total T3, total T4, free T4 were measured with an almost unmodified test (RIA) over the years. Results: The lowest relative coefficient of variation (<10%) was observed in the group of patients who had been treated with L-thyroxine only. Even for TSH, relatively low cofficients of variation were observed in this group. In the group of patients who had not received any medication, T3 and T4 showed also a variation of 10%. FT4 and TSH revealed a wider range of variation. Even after radioiodine therapy, T3 and T4 showed only a quite small variation, while TSH demonstrated a wide range with a variation of >30%. Conclusion: Our data demonstrate that there are only narrow variations of serum T4 and T3 within individuals with and without thyroid disorders.

scholarly journals The Effect of Perchlorate, Thiocyanate, and Nitrate on Thyroid Function in Workers Exposed to Perchlorate Long-Term

2005 ◽  
Vol 90 (2) ◽  
pp. 700-706 ◽  
Author(s):  
Lewis E. Braverman ◽  
XueMei He ◽  
Sam Pino ◽  
Mary Cross ◽  
Barbarajean Magnani ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Thyroid Volume ◽  
Production Plant ◽  
Sodium Iodide Symporter ◽  
Free T4 ◽  
High Exposure ◽  
Serum T4 ◽  
Serum Tsh ◽  
Serum And Urine

Perchlorate (ClO4−) and thiocyanate (SCN−) are potent and nitrate (NO3−) a weak competitive inhibitor of the thyroid sodium-iodide symporter. To determine the effects of long-term, high ClO4− exposure on thyroid function, we conducted a study of 29 workers employed for at least 1.7 yr (50% over 5.9 yr) in an ammonium ClO4− production plant in Utah. Serum ClO4−, SCN−, and NO3−; serum T4, free T4 index, total T3, thyroglobulin (Tg), and TSH; 14-h thyroid radioactive iodine uptake (RAIU); and urine iodine (I) and ClO4− were assessed after 3 d off (Pre) and during the last of three 12-h night shifts in the plant (During) and in 12 volunteers (C) not working in the plant. Serum and urine ClO4− were not detected in C; urine ClO4− was not detected in 12 of 29 and was 272 μg/liter in 17 Pre workers; serum ClO4− was not detected in 27 of 29 Pre; and serum and urine ClO4− were markedly elevated during ClO4− exposure to 868 μg/liter and 43 mg/g creatinine, respectively. Serum SCN− and NO3− concentrations were similar in all groups. Thyroid RAIUs were markedly decreased in During compared with Pre (13.5 vs. 21.5%; P &lt; 0.01, paired t) and were associated with an increase in urine I excretion (230 vs. 148 μg I/g Cr; P = 0.02, paired t) but were similar to those in the C group (14.4%). Serum TSH and Tg concentrations were normal and similar in the three groups. Serum T4 (8.3 vs. 7.7 μg/dl), free T4 index (2.4 vs. 2.2), and total T3 (147 vs. 134 ng/dl) were slightly but significantly increased in the During vs. Pre workers (P &lt; 0.01, paired t). Thyroid volumes and patterns by ultrasound were similar in the 29 workers and 12 community volunteers. In conclusion, high ClO4− absorption during three nights work exposure decreased the 14-h thyroid RAIU by 38% in ClO4− production workers compared with the RAIU after 3 d off. However, serum TSH and Tg concentrations and thyroid volume by ultrasound were not affected by ClO4−, suggesting that long-term, intermittent, high exposure to ClO4− does not induce hypothyroidism or goiter in adults.

scholarly journals Hyponatremia and Isolated Free T4 Elevation in a Patient With Acute Intermittent Porphyria

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A585-A586
Author(s):  
Anand Gandhi ◽  
Michael Mortensen ◽  
Mahmoud Alsayed ◽  
Aditi Kumar ◽  
Jerome H Targovnik
Keyword(s):  
Abdominal Pain ◽  
Thyroid Function ◽  
Aminolevulinic Acid ◽  
Acute Intermittent Porphyria ◽  
Laboratory Evaluation ◽  
Porphobilinogen Deaminase ◽  
Thyroid Function Tests ◽  
Free T4 ◽  
Deiodinase Activity ◽  
Wide Range

Abstract Background: Porphyrias represent a spectrum of diseases that stem from dysfunction within the heme biosynthetic pathway. Acute intermittent porphyria (AIP) is the most common type of porphyria due to a genetic deficiency of porphobilinogen deaminase which results in a wide range of neurovisceral symptoms. Hyponatremia and abnormalities with thyroid function have been found in AIP but the mechanisms behind these processes are unclear. Clinical Case: A 26-year-old male with a history of chronic, recurrent abdominal pain presented with 10 days of progressively worsening periumbilical abdominal pain and constipation. He describes that preceding the onset of symptoms he had been binging 5-10 standard alcoholic drinks each day for a few days. Initial laboratory workup demonstrated hyponatremia with Na 114 mmol/L (n: 134 – 137 mmol/L), hypochloremia with Cl 76 mmol/L (n: 95 – 108 mmol/L), and hyperbilirubinemia with total bilirubin 2.5 mg/dL (n: 0.2 – 1.3 mg/dL). CT abdomen/pelvis was negative for any concerning pathology. Further studies showed low serum osmolality at 243 mOsm/kg (n: 275 – 295 mOsm/kg), urine Na 62 mmol/L (n &gt; 20mmol/L), and urine osmolality at 394 mOsm/kg (n: 300 – 900 mOsm/kg) consistent with SIADH. The patient was treated with 3% NaCl and free water restriction to 1.2L/day with improvement in Na levels. Further laboratory workup demonstrated normal TSH, but persistently elevated free T4 with maximum free T4 of 2.77 ng/dL (n: 0.80 – 1.70 ng/dL) which downtrended to 1.99 ng/dL by discharge. Thyroid ultrasound was unremarkable. Pituitary evaluation via hormonal workup and MRI brain was negative for any abnormalities. Given the symptomatology and laboratory findings, the patient was evaluated for porphyria. Laboratory evaluation demonstrated severe elevations in urine porphyrins, urine delta aminolevulinic acid (56.8 mg/24h, n &lt; 4.5 mg/24h), and urine porphobilinogen (82.5 mg/g, n &lt; 2.3 mg/g) consistent with AIP. The patient was treated with four days of hematin infusions which resolved his abdominal pain and was discharged in an improved state. Conclusion: AIP is a rare entity brought out by a deficiency in porphobilinogen deaminase, a key enzyme in the heme biosynthesis pathway. Various metabolic disturbances have been described in AIP including hyponatremia and alterations in thyroid function tests suggestive of thyrotoxicosis. Hyponatremia in our patient was likely due to SIADH from neurovisceral pain. Our patient displayed isolated free T4 elevation as well. We hypothesize this developed due to his acute illness causing a greater decrease in D2 deiodinase activity compared to any concomitant increase in D3 deiodinase activity. This was supported by his free T4 level downtrending following treatment of his AIP attack. More research is needed to further elucidate the mechanism behind these derangements in biochemical markers and their impact on patient prognosis.

Could Thyroid Disorders Be Better Understood and Dealt as a Thyroid Syndrome

2020 ◽  
Vol 5 (08) ◽  
pp. 326-328
Author(s):  
Dr. Sushma Patil ◽  
Dr. Vikrant Patil
Keyword(s):  
Reference Range ◽  
Well Being ◽  
Thyroid Disorders ◽  
Thyroid Function Tests ◽  
Thyroid Disorder ◽  
Serum Concentrations ◽  
Comorbid Conditions ◽  
Free T4 ◽  
Research Perspective ◽  
Wide Range

Thyroid disorders are common worldwide. Thyroid dysfunction, both hypo- and hyperthyroidism may increase the risk of cardiovascular disorders. Current thyroid function tests may have limitations since they only measure the total or free T4 and/or T3 and TSH serum concentrations in peripheral blood and not the effect of T4 or T3 serum on different specific target tissues. Several comorbid conditions can interfere with the absorption or increase the clearance of levothyroxine. Among patients treated with thyroid replacement, under or overmedicated may-be at risk for adverse health consequences. A wide range of drugs may interfere with levothyroxine absorption, metabolism, and action. Patients report a lack of well-being, despite reaching euthyroid reference range of TSH, with psychological distress. If we will consider Thyroid related conditions as a syndrome then research perspective at the pathophysiology, interrelation between symptoms and comorbidities will be much broader that can lead researchers to get insights of different pathways in which thyroid gland functioning can be perceived and dealt therapeutically. The deliberation of thyroid disorder as a syndrome can affluence our knowledge of correlating cofounders, action of thyroid hormones on target tissues, underlying cause and thyroid health.

scholarly journals The T4:TBG Ratio: A Re-Evaluation with Particular Reference to Low and High Serum TBG Levels

1982 ◽  
Vol 19 (2) ◽  
pp. 101-103 ◽  
Author(s):  
E C Attwood ◽  
G E Atkin
Keyword(s):  
Retrospective Study ◽  
Thyroid Function ◽  
Reference Range ◽  
High Serum ◽  
Reference Ranges ◽  
Thyroid Function Tests ◽  
Thyroxine Binding Globulin ◽  
Biochemical Investigation ◽  
Small Increments ◽  
Routine Assay

The thyroxine: thyroxine-binding globulin (T4: TBG) ratio is now an established part of the biochemical investigation of thyroid function. Reference ranges have been reported for euthyroid subjects with TBG levels within the range 6–16 mg/l. Routine assay of TBG on all thyroid function tests in this laboratory has suggested that, in patients with low or high TBG levels, the established reference ranges for T4:TBG may not be strictly applicable. A retrospective study has been made of a large number of thyroid function requests, including serum total T4, free T4, TBG, and TSH assays. Evidence is presented to show that in subjects with a TBG level of less than 8 mg/l the reference range for T4: TBG is elevated. Similarly, in subjects with a TBG greater than 16 mg/l, the reference range for T4: TBG is lowered. The data suggest that it is necessary to quote a T4: TBG reference range based on small increments of TBG levels or to relate total T4 reference ranges to those increments.

Young adult reference ranges for thyroid function tests on the Centaur immunoassay analyser

2006 ◽  
Vol 63 (4) ◽  
pp. 163-165 ◽  
Author(s):  
M. Alqahatani ◽  
W. Tamimi ◽  
M Aldaker ◽  
F. Alenzi ◽  
H. Tamim ◽  
...  
Keyword(s):  
Young Adult ◽  
Thyroid Function ◽  
Reference Ranges ◽  
Thyroid Function Tests ◽  
Function Tests

scholarly journals Case Report: De Quervain’s Thyroiditis as a Long-Term Sequelae Complication to SARS-CoV-2 Infection

2021 ◽  
pp. 64-70
Author(s):  
Mark Kong ◽  
Sarah La Porte
Keyword(s):  
Case Report ◽  
Thyroid Function ◽  
Elevated Serum ◽  
Subacute Thyroiditis ◽  
Thyroid Function Tests ◽  
Thyroid Function Testing ◽  
Neck Lump ◽  
Function Testing

A 44-year-old man presented with an enlarged painful lower anterior neck lump with elevated serum concentrations of free thyroxine (T4) and tri-iodothyronine (T3), alongside the presence of antithyroid peroxidase antibodies. Prior to presentation, the patient was demonstrating recovery from a SARS-CoV-2 infection that required sedation, intubation, and invasive ventilation in the intensive care unit (ICU) for 11 days. Ultrasound examination of the thyroid demonstrated features of De Quervain’s (subacute) thyroiditis. This corresponded to the clinical picture, and continuous thyroid function tests were arranged. Emerging evidence throughout the SARS-CoV-2 pandemic describes the long-term sequelae of the infection, including developing atypical effects on the thyroid gland. This case report emphasises the association of painful subacute thyroiditis with post-viral infection and its manifestation during recovery from severe SARS-CoV-2, suggesting that follow-up thyroid function testing should be considered in patients discharged from the ICU who develop neck discomfort.

scholarly journals A comparative study on outcomes of preprandial versus postprandial thyroid function test

2019 ◽  
Vol 5 (6) ◽  
pp. 1662
Author(s):  
Vasim Ismail Patel ◽  
Akshay B. K.
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Clinical Symptoms ◽  
Thyroid Function Test ◽  
Thyroid Stimulating Hormone ◽  
Endocrine Gland ◽  
Thyroid Function Tests ◽  
Sample Collection ◽  
Free T4 ◽  
Group 2

<p class="abstract"><strong>Background:</strong> The thyroid is an<strong> </strong>endocrine gland. It secretes two hormones thyroxine (T<sub>4</sub>), triiodothyronine (T<sub>3</sub>). Hypothyroidism is a common condition encountered by a clinician. Subclinical hypothyroidism (SCH) defined as normal free thyroxine (T4) and elevated thyroid stimulating hormone (TSH), is primarily a biochemical diagnosis with or without clinical symptoms. Studies have observed that TSH levels vary at different times in a day. In practice not much importance is given to the timing of the sample collection (pre-prandial or post-prandial sate). SCH is diagnosed depending on TSH value. So the condition may be under or over diagnosed based on a single value. So we conducted this study to determine whether timing of sample collection had any significant relationship in the determination of levels of thyroid hormones.</p><p class="abstract"><strong>Methods:</strong> The study was carried on 114 patients who visited ENT department, NMCH between July 2018 and June 2019. Group-1 consisted of 38 normal patients. Group-2 consisted of 36 hypothyroidism patients GROUP-3 consisted of 40 subclinical hypothyroidism patients. Thyroid function tests (TSH and free T4) were done in fasting state and 2 hours postprandially.  </p><p class="abstract"><strong>Results:</strong> TSH values were found to be significantly lowered after food in all the three groups. Free T4 values did not show any statistically significant alteration after food.</p><p class="abstract"><strong>Conclusions:</strong> There was a significant decline in TSH values postprandially. This might lead to inappropriate diagnosis and management of patients as cases of hypothyroidism, especially in cases of sub clinical hypothyroidism.</p>

scholarly journals Familial Dysalbuminaemic Hyperthyroxinaemia and Other Causes of Euthyroid Hyperthyroxinaemia

1987 ◽  
Vol 80 (12) ◽  
pp. 750-752 ◽  
Author(s):  
C Farror ◽  
M L Wellby ◽  
C Beng
Keyword(s):  
Thyroid Function ◽  
Equilibrium Dialysis ◽  
Elevated Serum ◽  
Normal Serum ◽  
Thyroid Function Tests ◽  
Free T4 ◽  
Incorrect Diagnosis ◽  
Biochemical Studies ◽  
Autosomal Dominance ◽  
Clinical Awareness

Clinical and biochemical studies on a family in which 3 members have familial dysalbuminaemic hyperthyroxinaemia (FDH) are presented. They were clinically euthyroid with elevated serum thyroxine (T4) and free T4 indices but normal free T4 by equilibrium dialysis and normal serum triiodothyronine (total and free). All thyroid function tests on the remaining family members were normal. The inheritance is consistent with autosomal dominance. Also presented are data on 4 unrelated patients with FDH and two patients with T4 autoantibodies. The methods for detecting FDH, T4 antibodies and other causes of euthyroid hyperthyroxinaemia are now freely available. Since these anomalies may be more common than previously supposed, clinical awareness of the conditions is necessary to protect patients from the consequences of incorrect diagnosis of thyrotoxicosis.

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