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3 Reasons for Low TSH Normal T4 Results

نشرت بواسطة:Dr.Megan Ralf December 04, 2024 في T4, Thyroid, TSH

<p><i><b> Low TSH normal T4 is called subclinical hyperthyroid which means incomplete hyperthyroidism, subclinical means a case of normal body function but blood test results show a little increase or decrease out the normal range,  hyperthyroid mean over production of thyroid hormone (T3 and T4).</b></i></p><h3 style="text-align: left;"><strong>What this topic taking about</strong></h3>
<ul>
<li>What does low TSH with normal thyroid hormone means?</li>
<li>Low TSH normal T4 T3 causes and symptoms.</li>
<li>What should you concern about?</li>
<li>Does subclinical hyperthyroidism need treatment?</li>
<li>Do low TSH and normal T4 cause death?</li>
</ul>
<p><span style="text-decoration-line: underline;">Note that:</span><br />
Thyroid gland is a butterfly shaped gland, set in front of the trachea.<br />
T3 means is the total concentration (free and bound) of tri-iodo thyronine hormone.<br />
T4 means is the total concentration (free and bound) of thyroxine hormone.</p><p>T3 and T4 is two hormones produced by the thyroid gland after stimulation by the hormone TSH which secreted by the pituitary gland, both T3 and T4 are called thyroid hormone, thyroid hormone function is to initialize the metabolism, thus the body start processing substances circulating in the blood.</p><p>Free T3 is the free form of T3 hormone (unbound to a carrier protein).<br />
Free T4 is the free or unbound form of T4 hormone.</p><p>The free form of the thyroid hormone is the active form and circulate without attaching to a carrier protein, FT3 and FT4 are better for diagnosis than T3 and T4 especially when blood proteins are high</p><p><b><span style="text-decoration-line: underline;">The full story is:</span><br /></b>
The T3 and/or T4 is decreased in the blood (hypothyroid), the pituitary gland sensitive to the thyroid hormone level, the pituitary secrete the thyroid stimulating hormone (TSH) to stimulate the thyroid gland to produce more T3 and T4, TSH stops stimulation when T3 and/or T4 become within normal range, this process called homeostasis loop and means the human body adjust normal levels all the time.</p><p>TSH outside the reference range is likely to indicate that tri-iodothyronine and thyroxine levels are not normal for that particular person. Due to the log linear negative feedback relationship between serum thyroid hormone and TSH, even a small increase in serum thyroid hormone can suppress TSH secretion. Whether there is a difference between patients with a low, but detectable TSH versus patients with a fully suppressed TSH is unclear.</p><h4 style="text-align: left;"><strong>Subclinical hyperthyroidism definition:</strong></h4>
<ul>
<li>Subtle or unclear symptoms of hyperthyroidism</li>
<li>Low or undetectable TSH level</li>
<li>Normal or slightly increased T4,T3 with low TSH</li>
</ul>
<p></p><h4 style="text-align: left;"><strong>Low TSH normal T4 symptoms and Signs:</strong></h4>
Patients with low TSH and normal T4 T3 levels, whether due to exogenous causes or endogenous causes, were found to have a higher prevalence of heart palpitations, tremor, heat intolerance signs, sweating, nervousness, and anxiety, but many cases not overt symptoms of hyperthyroidism and thyroid gland work with autonomy function.<p></p><p></p><h4 style="text-align: left;"><strong>Examples for TSH low T4 normal:</strong></h4>
<span style="text-decoration-line: underline;">1. Female non pregnant, 35 years old results:</span><br />
Tsh less than 0.1 (<0.1 mU/l), Normal TSH level for adults is 0.3 – 4.5 mIU/ml, the result is lower than normal range.<br />
FT3 2.5, normal FT3 for adults is 1.5 – 4,2 pg/ml, normal result.<br />
FT4 1.2, normal FT4 for adults is 0.9 – 1.9 ng/dl, normal result.<p></p><p><span style="text-decoration-line: underline;">2. Adult male, 40 years old, diagnosed for hyperthyroidism</span><br />
First diagnostic results:<br />
TSH 49 mIU/ml, T3 0.71 ng/dl, T4 4.1 ug/dl, results show high TSH and low T3 T4.<br />
After period with treatment<br />
Tsh less than 0.3, T3 1.5 ng/dl, T4 8.5 ug/dl, results show low TSH normal T3 T4<br />
Normal T3 range for adults is 0.8 - 2.1 ng/dl, normal T4 range for adults is 4.6 – 12.5 ug/dl<br />
<span style="text-decoration-line: underline;">3. Very low or undetectable TSH levels</span>: TSH 0.005 or less, T3 1.8 ng/dl, T4 10.0 ug/dl, the results may increase after rechecking within a month and show overt hyperthyroidism symptoms, especially if ultrasound show small or large nodule.<br />
<em>Read: <a href="http://www.bloodtestsresults.com/normal-tsh-levels-normal-tsh-level-by-age/">Normal TSH levels</a> chart by age</em></p>
<h2><strong>Causes of low TSH normal T4 and T3 results:</strong></h2>
<p><span style="text-decoration-line: underline;"><strong>Normal body function</strong></span><br />
Medical term is homeostasis:<br />
Subclinical hyperthyroidism shows low TSH in a healthy person in general, body needs may cause short term changes in hormonal levels which appear as little abnormal results, considered normalized body balance and should go inside normal ranges soon.</p>
<ol>
<li>15% of whom have low TSH T4 normal is older patients.</li>
<li>Common low TSH normal T4 during pregnancy: Because B-hCG hormone has some thyroid stimulating activity, TSH may be suppressed during the first trimester.</li>
</ol>
<p></p><h3 style="text-align: left;"><span style="text-decoration-line: underline;"><strong>Causes from outside the thyroid gland</strong></span></h3>
Medical term is exogenous<p></p><p><span style="text-decoration-line: underline;">Exogenous subclinical hyperthyroidism</span> due to <strong>non-thyroidal illness</strong>, sometime called non-thyroidal illness syndrome (NTIS): thyroid allostasis in critical illness, tumors, uremia and starvation (TACITUS), non-thyroid illness syndrome can cause three euthyroid states, transient depression in TSH, T3, and T4, or low TSH, T3 and slightly high T4, or slightly high TSH and T3 T4 normal when recovery.</p><p><span style="text-decoration-line: underline;">Iatrogenic subclinical hyperthyroidism</span>: caused by using treatment drugs, the use of TSH suppressing medication other than thyroid hormone (for example, glucocorticoids, dopamine), using oral glucocorticoids (e.g. cortisone) is a known cause of suppression of TSH level without high T4.</p><p>Intentional suppressive thyroid hormone therapy, as in patients with <a href="http://www.bloodtestsresults.com/what-tests-should-be-done-to-detect-the-presence-of-tumor-and-cancer/">thyroid cancer</a>, thyroid nodules, or goiter.</p><p>In endogenous subclinical hyperthyroidism due to multinodular goiter, there seems to be a pattern of slow progression towards overt hyperthyroidism.</p><p>Overzealous thyroid hormone replacement therapy suppresses TSH production with normal thyroid hormone level.</p>
<p></p><h3 style="text-align: left;"><span style="text-decoration-line: underline;"><strong>Causes from inside the thyroid gland</strong></span></h3>
Medical term is endogenous<br />
<span style="text-decoration-line: underline;">Endogenous subclinical hyperthyroidism</span>, the source of the mild excess of thyroid hormone in the blood circulation is the thyroid itself, as in Graves’ disease, multinodular goitre, solitary functioning thyroid nodules, or thyroiditis by viral infection.<br />
<h4 style="text-align: left;"><strong>Is low TSH normal T4 dangerous or cause cancer? </strong></h4><p></p>
<ul>
<li>High mortality rate is not clearly understood according to many scientific studies.</li>
<li>Low TSH normal T4 is not clearly associated with developing cardiovascular disease, can induce cardiac dysfunction is less clear</li>
<li>TSH low t4 normal may be developed to hyperthyroidism within 7-10 years especially in elders over 55, some other cases not became overtly hyperthyroid nor euthyroid during such period of time.</li>
<li>Ultrasound findings (enlargement, nodules) predict, confirm, or decline abnormal thyroid integrity.</li>
<li>Med-annual or annual checkup is recommended particularly in those where TSH remains persistently undetectable.<br />
Read: Recommended <a href="http://www.bloodtestsresults.com/blood-test-for-thyroid-function-thyroid-cancer/">blood test for thyroid function</a></li>
</ul>
<p><span style="text-decoration-line: underline;">According to some studies:</span><br />
Biondi et al found more atrial premature beats and a 20% higher mean heart rate in 20 relatively young patients with iatrogenic subclinical hyperthyroidism, compared with controls. In addition, echocardiographic measurements showed evidence of left ventricular hypertrophy in six of 20 patients.<br />
All of whom had been treated with TSH suppressive doses of L-thyroxine for at least five years and all of whom complained of exertional dyspnoea. </p><p>Both myocardial hypertrophy and diastolic dysfunction improved after treatment with β-blocking agents. Six months of individual tailoring of the TSH suppressive L-thyroxine dose aiming at a TSH of 0.1 mU/l was associated with normalization of echocardiographic parameters and an increase in maximal workload</p><p>Sgarbi et al treated 10 patients, median age 59 years, with endogenous subclinical hyperthyroidism due to a multinodular goitre (n = 5), a solitary functioning thyroid nodule (n = 2), or a diffuse goitre (n = 3) for six months with antithyroid therapy. After reaching euthyroidism they found a significant decrease in heart rate and in the number of atrial and ventricular premature beats. Echocardiography demonstrated a reduction of the left ventricular mass index, interventricular septum thickness, and left ventricular posterior wall thickness at diastole.</p><p>In conclusion, the majority of data suggest that thyroid hormone levels above the hypothalamic-pituitary set point (low TSH normal T4) have a negative effect on cardiac function and morphology. Furthermore, subclinical hyperthyroidism is associated with a significantly increased risk on atrial fibrillation.</p><h3 style="text-align: left;"><span style="text-decoration-line: underline;"><strong>What should you concern about?</strong></span></h3>
Recheck the thyroid tests if it’s suspicious or the laboratory procedures not done correctly.<div><br /></div><div>If you taking thyroid medication, then you know why you have low TSH and normal T4 T3</div><div><br /></div><div>If it’s the first time to test for thyroid hormones and found low TSH level than normal reference range but T3, T4, FT3, and FT4 is normal, you must know that it’s called subclinical or incomplete hyperthyroidism, <br />you must repeat the thyroid test after period of time to ensure TSH become normal, but most clinicians prefer to perform ultrasound imaging after subclinical hyperthyroidism for early detection of nodules or cancers, if Uls results are OK, then you only need to follow up by thyroid blood tests after several months.<br /><ul>
</ul>
<p><i>We are welcome to answer questions and explain your results for free.</i></p></div>

Low TSH normal T4 is called subclinical hyperthyroid which means incomplete hyperthyroidism, subclinical means a case of normal body functi... Read More »

TSH Normal Range by Age Thyroid Levels chart (Tsh Levels Chart)

نشرت بواسطة:Dr.Megan Ralf December 04, 2024 في Thyroid, TSH

<p><i><b> Come here to know, what are normal TSH levels, safe TSH ranges, and what does Normal TSH level mean in your blood test?</b></i></p><p>
TSH is the Thyroid Stimulating Hormone, initial thyroid function marker.<br />Factors cause normal shift in TSH reference ranges<br />The normal reference ranges for TSH blood test levels go up and down slightly as the human grow older and has a small shift for pregnant:<br />Small variations in TSH ranges can occur due to different laboratory methods used and the time of day your blood TSH test was taken.</p><p></p><h4 style="text-align: left;">
What is a normal TSH level?</h4>
Normal TSH level means the TSH blood test values and numbers that studies in people with healthy thyroid function tests.<p></p><p>Normal levels of tsh test is an indicator of a healthy thyroid gland, which means no hypothyroidism with these numbers, and no cancer with these numbers as well, although a case called "<b><i>Euthyroid</i></b>" shows normal TSH levels with unreal/untrue high thyroid hormone levels.</p><p>Normal TSH levels for the average adult is from 0.4 4.5 mIU/L<br />
mIU/L means milli international units per liter of blood, a measurement unit for tsh 3rd generation normal ranges.</p><p>TSH normal values from zero to 2.5 is optimal.<br />
TSH test results from 2.6 to 4.0 is at risk.<br />
Goal TSH level for patients on thyroxine is between 0.5 to 2.5 mU/L.</p>
<h2>TSH Normal Levels chart by age</h2>
<p>Normal TSH levels for children<br />
For premature birth (newborn 28-36 weeks) is 0.7 27 mIU/L<br />
Normal TSH level for age 1 day – 1 week is 1.0 – 40.0 mIU/mL<br />
Normal TSH level for age 2 weeks – 1 month is 1.7 – 9.1 mIU/mL<br />
Normal TSH level for age 2 months – 1 year is 0.8 – 6.4 mIU/mL<br />
Normal TSH level for age 2 years – 5 years is 0.7 – 5.4 mIU/mL<br />
Normal TSH level for age 6 years – 10 years is 0.53 – 5.3 mIU/mL<br />
Normal TSH level for age 11 years – 18 years is 0.5 – 5.0 mIU/mL<br />
Chart of normal TSH levels for adult man and adult non-pregnant woman<br />
Age 21 54 years is 0.4 4.2 mIU/L<br />
Age 55 87 years is 0.5 8.9 mIU/L<br />
</p><h3 style="text-align: left;"><strong>Chart of TSH normal levels during pregnancy</strong></h3>
First trimester normal TSH is 0.1 - 2.5 mIU/L<br />
Second trimester normal TSH is 0.2 - 3.0 mIU/L<br />
Third trimester normal level of TSH is 0.3 - 3.0 mIU/L<br />
TSH is the most well-studied marker for <a href="http://www.bloodtestsresults.com/blood-test-for-thyroid-function-thyroid-cancer.html">thyroid function</a> evaluation.<br />
TSH is considered the most sensitive and accurate indicator of thyroid function by most endocrinologists and other doctors.<p></p><p>TSH normal reference ranges are from the American Thyroid Association and published in the journal Thyroid.</p><p><em>Also, some thyroid testing kits may recommend another normal reference.</em><br />
After presenting what is the normal range for TSH blood test, a new publication about TSH results comes soon. SUBSCRIBE to get free explanation of your results,</p>

TSH Normal Range by Age Thyroid Levels chart (Tsh Levels Chart)

Come here to know, what are normal TSH levels, safe TSH ranges, and what does Normal TSH level mean in your blood test? TSH is the Thyroid... Read More »

What Blood Test For Thyroid Gland Function and Cancer

نشرت بواسطة:Dr.Megan Ralf December 04, 2024 في Thyroid, TSH

<p> The basic Blood test for thyroid gland function is TSH, total T4, total T3, Free T4, and Free T3. But the thyroid test cost is high, so that must know when to test for each one, and what's the clinical need for thyroid function tests and what's the accurate blood test for thyroid?</p><p>
</p><h3 style="text-align: left;"><span style="text-decoration-line: underline;"><strong>What blood test for thyroid function screening</strong></span></h3>
TSH blood test is the one-test screen for patients with non-specific symptoms such as tiredness. A level between 0.4 and 4 mU/L gives 99% exclusion of hyperthyroidism or hypothyroidism.<p></p><p></p><h4 style="text-align: left;"><strong>T4 blood test is added when:</strong></h4>
• when there are more specific symptoms of thyroid disease such as tachycardia, atrial fibrillation, weight loss, cold or heat intolerance etc.<br />
• when monitoring thyroid therapy<br />
• suspected hypopituitarism<br />
<h4 style="text-align: left;"><strong>T3 blood test is added when thyrotoxicosis is suspected.</strong></h4>
The combination of clinical and laboratory features will indicate probable status as hyperthyroid, hypothyroid or euthyroid. More about each case later..<br />
<h3 style="text-align: left;"><strong>What do Thyroid Function Tests mean?</strong></h3>
Laboratory <strong>blood test for </strong>thyroid function is TSH, T3, T4, Free Thyroxine, Free T3, T3 Resin Uptake T3RU, and Thyroid Antibodies, however Lab tests for routine thyroid checkup are TSH and T3.<p></p>
<ul>
<li>Thyroid tests are tested from a blood sample taken from your arm.</li>
<li>The thyroid gland produces three hormones: thyroxine (T4), triiodothyronine (T3) and calcitonin. T3 and T4 are collectively referred to as thyroid hormone.</li>
<li>Thyroid hormone controls cellular metabolic activity and is critical to brain development and growth.</li>
<li>Thyroid hormone secretion is controlled by TSH from the anterior pituitary gland, TSH means thyroid stimulating hormone.</li>
</ul>
<h4 style="text-align: left;"><strong>Thyroid-stimulating Hormone (TSH) test</strong></h4>
<ul>
<li>TSH is the best screening test for thyroid function.</li>
<li>Increased TSH levels indicate hypothyroidism; decreased TSH levels indicate hyperthyroidism.</li>
<li>TSH used to monitor thyroid hormone replacement therapy.</li>
</ul>
<p></p><h4 style="text-align: left;"><strong>Thyroxine Screening test (T4 test)</strong></h4>
T4 is the major hormone produced by the thyroid gland. Controls basal metabolic rate.<br />
T4 used to screen for and diagnose hypothyroidism or hyperthyroidism.<br />
Total T4 blood test measures all the T4 forms both protein bound (96–99%) and free (1–4%).<br />
<h4 style="text-align: left;"><strong>Free Thyroxine blood test (FT4 test)</strong></h4>
Free T4 is more accurate than total T4 test, as “Free” T3 and T4 are the metabolically “active” hormones in the plasma.<br />
Total T4 levels can be affected by protein levels in the blood and therefore give <a href="http://www.bloodtestsresults.com/What-does-false-positive-and-false-negative-means.html">false results</a>.<br />
Free or unbound T4 is measured in patients with protein abnormalities to get a more accurate indicator of thyroid<br />
hormone.<br />
<h4 style="text-align: left;"><strong>Triiodothyronine Screening test (T3 test)</strong></h4><p></p>
<ul>
<li>Scientifically referred as T3 Radioimmunoassay</li>
<li>T3 is the major hormone produced by the thyroid gland from the T4 hormone, Used primarily to aid in the diagnosis of hyperthyroidism.</li>
<li>T3 is 3 to 5 times more active than T4</li>
<li>Has a more rapid onset of action</li>
<li>It is also more rapidly degraded in the body.</li>
</ul>
<p></p><h4 style="text-align: left;"><strong>T3 Resin Uptake test</strong></h4>
Other names of the test are T3RU, RT3U, Resin T3 Uptake<br />
Reference range for T3RU is 24–37%<br />
Measures the percentage of thyroid hormone bound to protein and therefore indicates the percentage of binding sites available.<br />
T3 uptake result 37% indicates number of available binding sites is low, which occurs in hyperthyroidism.<br />
T3 uptake result 37% indicates number of available binding sites is high, which occurs in hypothyroidism.<br />
<h4 style="text-align: left;"><strong>Thyroid Antibodies blood test for thyroid under function and cancer.</strong></h4>
They are Antithyroglobulin Antibody and Antimicrosomal Antibody<br />
Confirm the cause of thyroid dysfunction (loss of thyroid function).<br />
Microsomal antibodies are produced in response to microsomes released from damaged thyroid cells.<br />
<h4 style="text-align: left;"><strong>Calcitonin is a blood test for thyroid cancer</strong></h4>
Calcitonin is a hypocalcaemic hormone produced naturally by the parathyroid cells. There are no clinical excess or deficiency states.<br />
Calcitonin reduces circulating calcium levels by increasing calcium’s deposition in bone.<br />
Calcitonin used in the assessment of thyroid medullary cancer, lung cancer, pernicious anemia.<br />
<h3 style="text-align: left;"><strong>Blood tests for Thyroid diseases symptoms</strong></h3>
<span style="line-height: 1.5;">Thyroid gland is a large ductless gland in the neck that secretes hormones regulating growth and development through the rate of metabolism, thus abnormal secretions of thyroid hormone lead to </span>disturbances<span style="line-height: 1.5;"> in many body biological processes. For such reasons the correct thyroid disease follow up must include these lab tests:</span><p></p>
<ol>
<li>Liver function tests: Hypothyroidism is a reason of high bilirubin level (Hyperbiliruinaemia) with normal liver enzymes.</li>
<li>Blood lipogram test: Hypothyroidism is a risk factor of <a href="http://www.bloodtestsresults.com/My-cholesterol-level-is-high-what-does-this-means.html">elevated Cholesterol</a> LDL which is a major risk factor for coronary artery disease,</li>
<li>Serum Triglycerides: TG levels show abnormal results.</li>
<li>Serum CK test: Hypothyroidism –causes Elevations of total serum CK (creatine kinase).</li>
<li><a href="http://www.bloodtestsresults.com/Why-my-blood-tests-show-high-blood-glucose-levels-hyperglycemia.html">Glucose Blood test</a>: Hypothyroidism causes Diabetes mellitus (DM) through endocrinopathy.</li>
<li>Serum Calcium test: Calcium levels are increased in hyperthyroidism. Hypocalcaemia due to hypoparathyroidism which is usually post-thyroidectomy.</li>
<li><a href="http://www.bloodtestsresults.com/category/cbc-blood-test">Complete blood count</a> test: An increased neutrophil count may indicate thyroiditis. Decreased neutrophils by Antithyroid drugs, <a href="http://www.bloodtestsresults.com/What-does-low-hemoglobin-levels-means-in-a-blood-picture-test.html">Anemia </a>norocytic or macrocytic</li>
<li>Xylose Tolerance test: Decreased XTT levels seen in thyroid disease</li>
<li>Carotene test: hypothyroidism can cause carotenaemia.</li>
<li>Digoxin test: Hypothyroidism and some drugs raise digoxin levels.</li>
<li>TSH/T4 used for excluding hyperthyroidism in diagnosis of Anorexia nervosa and bulimia.</li></ol><div style="text-align: center;"><b><br /></b></div><h3 style="text-align: left;"><strong style="margin-left: 1em; margin-right: 1em; text-align: center;">Conclusion:</strong></h3><div><h4 style="text-align: left;">I. Tests based on primary function of thyroid, viz. substrate input and hormone synthesis</h4><p>
• Radioiodine “uptake” studies and ‘turnover’ (RAI or RIU) studies<br />
• PBI131 in serum<br />
• T3-suppression test<br />
• TSH-stimulation test<br />
• TRH-stimulation test.</p><p></p><h4 style="text-align: left;">II. Tests measuring blood levels of thyroid hormones</h4>
• Serum PBI and BEI<br />
• Circulating T3 and T4 level<br />
• Circulating TSH level<br />
• In vitro resin-uptake of T3<br />
• Plasma tyrosine level<p></p><p></p><h4 style="text-align: left;">III. Tests based on metabolic effects of thyroid hormones</h4>
• BMR<br />
• Serum cholesterol level<br />
• Serum creatine level<br />
• Serum uric acid<br />
• Serum CK enzyme.<p></p><p></p><h4 style="text-align: left;">IV. “Scanning” of thyroid gland</h4>
V. Immunological tests to detect autoimmune diseases of thyroid gland<br />
• Agar gel diffusion test (precipitation test)<br />
• TRCH test: Tanned red cells haemagglutination test.<br />
• Complement fixation test.<br />
<h4 style="text-align: left;"><strong>Common Ultrasound Tests:</strong></h4>
Assess mass or nodule; follow-up to abnormal thyroid blood tests, history of neck irradiation, or abnormality seen on other tests.<br />
<h4 style="text-align: left;"><strong>Nuclear Thyroid Scan:</strong></h4>
Determine thyroid size, function, and position and evaluate functional status of thyroid nodules.<br />
Evaluate of thyroid and neck masses.<br />
Evaluate of patients with history of head and neck irradiation.<br />
Quantitative thyroid uptake (I-131 uptake).<p></p>
<blockquote><p>Next is How to read and understand Thyroid function test results?</p></blockquote></div>

What Blood Test For Thyroid Gland Function and Cancer

The basic Blood test for thyroid gland function is TSH, total T4, total T3, Free T4, and Free T3. But the thyroid test cost is high, so tha... Read More »