When Should I Get A Tsh Test
TSH is often the first test doctors order when they suspect a patient has a thyroid disorder. Both hypothyroidism and hyperthyroidism are common disorders. All patients with symptoms of these thyroid disorders should have their TSH checked.
If you are having symptoms of these disorders, your doctor may order a TSH or a thyroid panel test. Symptoms of hypothyroidism include:
- Rapid or irregular heartbeat
- Loose, frequent bowel movements
TSH is also used to evaluate patients who are suspected to have other thyroid disorders, such as goiter, thyroid nodule, thyroid cancer, Graves disease, or Hashimotos thyroiditis. These disorders can cause hypothyroidism or hyperthyroidism.
Screening with TSH for hypothyroidism in adults is controversial. Screening means testing in the absence of symptoms. It is most beneficial when early detection and treatment of disease helps people avoid subsequent medical problems. Some organizations, such as the American Association of Clinical Endocrinology, the American Thyroid Association, and the Endocrine Society, favor routine screening for thyroid problems in adults without symptoms.
Because thyroid disorders can complicate pregnancy, screening with a TSH test during pregnancy is recommended for some women. Pregnant women without symptoms of thyroid problems may be screened if they:
What Is A Thyroid Function Test
A thyroid function test is a blood test to check the levels of the hormones made by your thyroid gland. The test also checks the level of a hormone made by the pituitary gland in your brain, which acts on your thyroid gland.
The two hormones, thyroxine and thyroid-stimulating hormone , work together and are usually in balance. In a healthy person the brain produces just the right amount of TSH to keep the thyroid gland ticking over. The thyroid gland then produces just the right amount of thyroxine.
This is called a feedback loop: if the thyroid gland makes too much thyroxine it will feed back to the brain to make less TSH. This diagram shows the feedback loop between the thyroid gland in your neck and the pituitary gland in the brain:
The Eight Blood Tests You Need To Assess Thyroid Function
December 6, 2017 by Megan
You didnt read that wrong. Thats right. I said the EIGHT blood tests for thyroid function assessment that you need to have run.
Now hold on, you think. My doctor only runs TWO blood tests for thyroid function TSH and T4. What am I missing??
Six other blood tests. Thats what youre missing.
Yes, TSH and T4 are important in the big picture of thyroid health, but without the other 6, MANY thyroid conditions often go undiagnosed. So you could be feeling like crap, wondering whats going on because your thyroid is normal according to your doctor.
Alright, lets get to it. Here are the EIGHT MOST IMPORTANT blood tests you need to have run in order to assess proper thyroid function.
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What Are Normal Thyroid Hormone Levels
The thyroid itself is regulated by another gland that is located in the brain, called the pituitary. In turn, the pituitary is regulated in part by the thyroid and by another gland called the hypothalamus.
The hypothalamus releases a hormone called thyrotropin releasing hormone , which sends a signal to the pituitary to release thyroid stimulating hormone . In turn, TSH sends a signal to the thyroid to release thyroid hormones. If a disruption occurs at any of these levels, a defect in thyroid hormone production may result in a deficiency of thyroid hormone .
Hypothalamus – TRH
Thyroid – T4 and T3
The rate of thyroid hormone production is controlled by the pituitary gland. If there is an insufficient amount of thyroid hormone circulating in the body to allow for normal functioning, the release of TSH is increased by the pituitary gland in an attempt to stimulate more thyroid hormone production. In contrast, when there is an excessive amount of circulating thyroid hormone, TSH levels fall as the pituitary attempts to decrease the production of thyroid hormone.
- In persons with hypothyroidism , there is a continuously decreased level of circulating thyroid hormones.
- In persons with hyperthyroidism , there is a continuously elevated level of circulating thyroid hormones.
Who Orders My Blood Tests
Your doctor typically orders blood tests for you during a physical, checkup, or an appointment intended for a specific condition.
Blood testing is usually partially or fully covered by insurance. Ordering tests through your medical provider ensures that youre not paying too much. Your doctor can also advise you on how to choose testing facilities that are reliable, well-managed, or convenient for you.
Its possible to order your own blood tests without a doctor or even health insurance, but its not recommended. You may end up paying the full cost by not going through an insurance plan, which can be expensive.
And some blood testing facilities may not give you accurate results. One infamous case of this is Theranos, a Palo Alto, California, biotechnology firm shut down in 2018 when an investigation uncovered lies and fraud around the accuracy of its private blood testing technology.
Normal levels can also vary by age.
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Blood Test Measurement Abbreviations
When you look at your blood work, you might see some abbreviations like pg or mmol/L. While confusing, these are abbreviations for the measurements for blood tests. Explore the various blood test measurement abbreviations.
- CMM – Cells Per Cubic Millimeter
- Da – Dalton
- fL – Femtoliter
- g/dL – Grams Per Deciliter
- IU/L – International Units Per Liter
- kPa – kilopascal
What Is A Tsh Test
Thyroid testsBlood tests to measure thyroid hormones are readily available and widely used. Not all thyroid tests are useful in all situations.
TSH TestThe best way to initially test thyroid function is to measure the TSH level in a blood sample. Changes in TSH can serve as an “early warning system” often occurring before the actual level of thyroid hormones in the body becomes too high or too low.
A high TSH level indicates that the thyroid gland is not making enough thyroid hormone . On the other hand, a low TSH level usually indicates that the thyroid is producing too much thyroid hormone . Occasionally, a low TSH may result from an abnormality in the pituitary gland, which prevents it from making enough TSH to stimulate the thyroid . In most healthy individuals, a normal TSH value means that the thyroid is functioning properly.
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Lab Tests Of Biopsy Samples
In some cases, doctors might use molecular tests to look for specific gene changes in the cancer cells. This might be done for different reasons:
- If FNA biopsy results arent clear, the doctor might order lab tests on the samples to see if there are changes in the BRAF or RET/PTC genes. Finding one of these changes makes thyroid cancer much more likely.
- For some types of thyroid cancer, molecular tests might be done to see if the cancer cells have changes in certain genes , which could mean that certain targeted drugs might be helpful in treating the cancer.
These tests can be done on tissue taken during a biopsy or surgery for thyroid cancer. If the biopsy sample is too small and all the molecular tests cant be done, the testing may also be done on blood that is taken from a vein, just like a regular blood draw.
T3 Resin Uptake Results
A T3 resin uptake, also known as a T3RU, is a blood test that measures the binding capacity of a hormone called thyroxin-binding globulin . If your T3 level is elevated, your TBG binding capacity should be low.
Abnormally low levels of TBG often indicate a problem with the kidneys or with the body not getting enough protein. Abnormally high levels of TBG suggest high levels of estrogen in the body. High estrogen levels may be caused by pregnancy, eating estrogen-rich foods, obesity, or hormone replacement therapy.
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What Are Thyroid Blood Tests And Why Are They Taken
Thyroid blood tests are used to tell if your thyroid gland is functioning properly by measuring the amount of thyroid hormones in your blood. They are done by withdrawing blood from a vein in your arm. These blood tests help to diagnose thyroid diseases.
The thyroid is a butterfly-shaped gland located in the front part of your neck. Its job is to produce thyroid hormones, which travel through your bloodstream and regulate many aspects of your bodys metabolism, including temperature, weight, and energy.
Thyroid blood tests show if you have:
- Hyperthyroidism: Overactive thyroid producing more thyroid hormones than your body needs. Hyperthyroidism speeds up your metabolism, which can cause weight loss, rapid heartbeat, insomnia, puffiness around the eyes, anxiety and other symptoms. The most common cause of hyperthyroidism is Graves disease.
- Hypothyroidism: Underactive thyroid producing too few thyroid hormones. Hypothyroidism slows down your metabolism, which can cause weight gain, menstrual irregularity, dry and puffy skin, fatigue and other symptoms. The most common cause of hypothyroidism is Hashimotos disease.
Thyroid blood tests are used to diagnose thyroid disorders associated with hyper- or hypothyroidism. These include:
What Does A Full Thyroid Panel Include
Thyroid stimulating hormone
âThe pituitary gland produces thyroid-stimulating hormone in the brain. The primary job of TSH is to regulate the amount of thyroid hormonesâthyroxine and triiodothyronine âproduced by the thyroid gland. This blood test measures how much overall thyroid-stimulating hormone is in your blood. While this is the standard test most doctors authorize, it won’t provide detailed information on your thyroid activity. For instance, it may not show problems like your body not being able to use the available thyroid hormone.
The thyroid produces two hormones: thyroxine and triiodothyronine . T4 is primarily inactive. Its primary job as a “storage hormone” is to transport T3 to the proper organs in your body. T4 must be converted to T3 before your body can use it to get energy or deliver oxygen to cells. The T4 test helps determine the level of thyroid hormone in the body however, it doesn’t provide enough information by itself because it can be affected by the amount of protein in your blood.
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Alternative Thyroid Test #: Total Cholesterol
This is another test youve likely had done, which is part of a standard lipid panel.
Keep in mind that we dont care about HDL vs. LDL. Ive written about why those dont matter in this post here.
We only care about total cholesterol.
Total cholesterol was one of the tests used to diagnosed hypothyroidism before TSH testing was developed.
The following cholesterol levels can indicate poor thyroid function:
- Above 230 mg/dL when not using a thyroid medication or supplement.
- Above 200 mg/dL when using a thyroid medication or supplement.
The Complete List Of Thyroid Lab Tests To Ask For
These lab tests represent ALL of the tests that are available for testing and evaluating thyroid function.
These tests are not always necessary, but they should be considered for your first visit to your physician.
They should also be coupled together with a complete physical exam and comprehensive history .
When you combine the power of advanced thyroid testing with a history and physical exam you should be able to adequately identify 98% of all thyroid disease states.
Note that this approach will take a significant amount of time .
#1. Thyroid Stimulating Hormone
The first test worth discussing is the TSH or thyroid stimulating hormone.
The TSH is secreted from a gland in your brain known as the pituitary gland and TSH is responsible for stimulating your thyroid gland to produce thyroid hormones .
One confusing aspect about TSH is that it isn’t always intuitive.
When TSH is high it generally means that your thyroid is not producing enough thyroid hormone.
When TSH is low it generally means that your thyroid is producing too much thyroid hormone.
But how can this be?
Why would your thyroid produce less thyroid hormone when TSH is high, especially since its name is thyroid STIMULATING hormone?
This is the confusing part about TSH!
The reason for this inverse relationship between thyroid hormones and TSH is that in most cases of hypothyroidism your thyroid gland is the main problem.
So TSH continues to rise while thyroid hormone levels continue to fall.
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Desiccated Thyroid Side Effects
Get emergency medical help if you have signs of an allergic reaction:hives difficult breathing swelling of your face, lips, tongue, or throat.
Common side effects may include temporary hair loss .
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What Is The Thyroid
The thyroid is a small gland below the skin and muscles at the front of the neck, at the spot where a bow tie would rest. It makes two types of thyroid hormones: T3 and T4 . It helps the body do many things, such as get energy from food, grow, and go through sexual development.
The pituitary is a pea-sized gland at the bottom of the brain that makes thyroid stimulating hormone . TSH triggers the thyroid to make more thyroid hormone. The pituitary gland and the thyroid gland send messages back and forth to each other about how much hormone to make to keep the levels normal.
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When Should I Get T4 Testing
There are a number of different reasons why a doctor might order a T4 test. Often it is ordered to follow up on an abnormal TSH test result.
It may also be used when a patient has symptoms that may be related to a thyroid disorder. Underactive thyroid and overactive thyroid are both common diseases. If you are having symptoms of these disorders, your doctor may order a T4 test in combination with other thyroid function tests, such as TSH and T3. This series of tests is also called a thyroid panel.
Hypothyroidism affects nearly 5% of adolescents and adults in the United States. Symptoms of hypothyroidism may include:
- Rapid or irregular heartbeat
- Loose, frequent bowel movements
There are additional reasons why a doctor might check a patients T4, such as monitoring the effectiveness of treatment with replacement thyroid hormones, screening newborns for congenital hypothyroidism, and to evaluate possible problems with the hypothalamus or pituitary gland.
What To Consider In Your Personal And Family Medical Histories
Its important to give your physician as many details as possible about your personal medical history, as well as family history . Be sure to discuss:
- Your general state of healthparticularly any changes you have noticed in your general overall health.
- Your familys health historyespecially if a close relative has been diagnosed with hypothyroidism .
- Whether youve ever had thyroid surgery, or radiation to your neck to treat cancer.
- Any medicines you may be taking that could cause hypothyroidism .
Physical ExaminationLooking for Signs of HypothyroidismYour physician will perform a thorough examination and look for physical signs of hypothyroidism, including:
- Evidence of dry skin
- Swelling around the eyes and legs
- Slower reflexes
- Slower heart rate
Blood Tests: Hypothyroidism can be detected by different blood tests.
- TSH Test. A thyroid-stimulating hormone or TSH is a blood test that measures the amount of T4 that the thyroid is being signaled to make. If you have an abnormally high level of TSH, it could mean you have hypothyroidism.
- T4 Test. The thyroid gland produces T4 . The free T4 and the free T4 index are blood tests that, in combination with a TSH test, can let your physician know how your thyroid is functioning.
Normal and Abnormal TSH Ranges
An easy way to remember how the thyroid works–think about supply and demand. As the T4 level falls, the TSH rises. As the T4 level rises, the TSH falls. However, not everyone with hypothyroidism has elevated levels of TSH.
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In Which Cases Is A Full Thyroid Panel Performed
As we mentioned previously, the levels of these hormones TSH, T3, and T4 can be affected by a number of various conditions. Lets list some of the most common conditions that cause an abnormality in the levels of TSH, T3, and T4 to occur.
Hyperthyroidism As you may know, hyperthyroidism is a term that is used to describe the over activity of the thyroid gland and the excessive production of the thyroid hormones due to which all the functions of the body increase their speed. The usual symptoms are increased heart rate, weight loss, diarrhea, anxiety, weakness, trouble sleeping, and tremors in the hands. What a full thyroid panel in a case of hyperthyroidism would show is low levels of TSH, and high or normal levels of T3 and T4 hormones.
Hypothyroidism Contrary to hyperthyroidism, hypothyroidism is a term that is used to define the condition in which your thyroid is not able to produce the needed levels of hormones in order to let your body function properly. It is also known as underactive thyroid disease, and surprisingly it is a very common condition. The usual symptoms of hypothyroidism include weight gain, constipation, fatigue, dry skin and menstrual irregularity. In a case of hypothyroidism, what the thyroid panel would show is high levels of TSH, and normal to low levels of T3 and T4 hormones.