The Thyroid-Stimulating Hormone (TSH) Test:
What You Need to Know about TSH Test
So, your doctor thinks your thyroid gland might not be functioning properly. Maybe you’ve been experiencing some puzzling signs and symptoms that are consistent with thyroid fluctuations, or perhaps routine blood work that you recently had done raised a red flag. Now you’ve been referred to a lab to have the TSH test performed.
The TSH test is a common laboratory procedure that is used whenever thyroid disorders are suspected. Basically, the test is designed to measure the amount of a specific thyroid hormone in the bloodstream. This week, we’ll take an in-depth look at this test, providing all of the information you need if you or a loved one has been referred to a lab for a TSH test.
What is the TSH Test Used to Detect?
The TSH test is used for one primary purpose: to quantify the amount of thyroid-stimulating hormone that is circulating in the bloodstream. Although its basic function is simple, the results gathered through the TSH test are an invaluable tool that doctors can use to diagnose and treat a wide array of health problems, including (but not limited to) the most common thyroid disorders, hyperthyroidism and hypothyroidism.
While the results of a TSH test offer doctors a powerful diagnostic tool in and of itself, patients often have the test performed along with a number of other procedures designed to track thyroid function and identify any possible problems. In many cases, the TSH test is ordered along with similar tests that measure other thyroid hormones, such as the T3 and the T4 tests. When all of these tests are performed simultaneously, the lab results that are gathered offer doctors a highly detailed portrait of how a patient’s thyroid gland and endocrine system are functioning.
When is the TSH Test Performed?
The TSH test is an important part of the ongoing care and treatment of any type of thyroid disorder, and patients with thyroid problems will likely undergo the test many times over the course of their treatment. However, this diagnostic tool is used in the care of an array of different health conditions. Here are some of the most common situations that may merit the TSH test:
- To help assess overall endocrine system function
- To evaluate the functionality of the pituitary gland
- To pinpoint the cause of fertility problems in women
- To verify adequate treatment of diagnosed cases of hyperthyroidism or hypothyroidism
- To check thyroid function in newborn babies
- To investigate the source of an enlarged thyroid gland or a nodule or bump in the neck area
- To monitor thyroid health and endocrine system function during pregnancy
- As part of a general check-up for adults over the age of 35
How are the TSH Test Results Interpreted?
There are as many different possible interpretations for TSH test results as there are reasons for ordering the procedure, so the best way to understand the implications of your test findings is to discuss the results with your primary care physician.
However, there are several general patterns in TSH test findings that can indicate a problem. Some of the most commonly observed findings include:
- High TSH levels – Specific diagnoses will vary, but high levels of thyroid-stimulating hormone in the bloodstream often indicate a case of hypothyroidism, or an under-active thyroid gland.
- Low TSH levels – Lower-than-average TSH readings may indicate an overactive thyroid gland. In some cases, this problem is the result of the disorder known as hyperthyroidism. In very rare instances, a low TSH level may be linked to a pituitary gland disorder.
- TSH levels within normal limits – Although your primary care physician should make the final determination, a normal TSH count may indicate that your thyroid gland is functioning normally. If you have been experiencing thyroid symptoms, the problems may have another source.
How Should I Prepare for the TSH test?
Any type of laboratory procedure can be stressful, particularly if you are sensitive to needles or the sight of blood. Make sure that you get plenty of rest beforehand, and try deep-breathing exercises if you experience any anxiety.
The thyroid gland is very sensitive to medications, so be sure to inform your doctor of any pharmaceutical treatments you are taking. Even seemingly innocent drugs such as aspirin or vitamin supplements could cause an anomaly in the test results, so err on the side of caution and report everything, just to be safe.
Your medical team will provide you with any special information you may need to get through the test. Be sure to ask questions if you’re confused by any aspect of the procedure. And be sure to check back here each week for more vital thyroid health information!
For Further Reading
So, Your Doctor Thinks You May Have a Thyroid Disorder -- Now What?
An Overview of Common Thyroid Tests
Finding out that your thyroid may not be functioning properly can be a disorienting and emotionally draining experience. This sense of feeling overwhelmed and confused can sometimes be made even worse by the battery of tests, lab procedures, and other diagnostic assessments that follows a preliminary diagnosis of thyroid-related problems.
Once your doctor has determined that the signs and symptoms you’ve been experiencing may be linked to your thyroid, the next step will be assessing the health and performance of your thyroid gland using a number of advanced diagnostic procedures.
Because thyroid disorders can encompass such a broad range of illnesses, diseases, and conditions, it is likely that you will be subjected to a sizable number of diagnostic tests. In order to pinpoint the precise nature and extent of the problem, your doctor may arrange a full slate of procedures, ranging from blood work to advanced imaging of the thyroid gland.
It’s likely that the less that your doctor knows about your thyroid disorder, the more tests he or she will schedule. This week, we’ll take a look at some of the most common tests that are used to gauge thyroid health, function, and disorders.
Because a dysfunctional thyroid gland can impact the level of hormones in your blood, blood tests are often an important component of the diagnostic process. Here are some common blood tests used to help identify possible thyroid problems.
- T3 levels - Blood tests are often used to determine the level of thyroid hormone triiodothyronine in the bloodstream.
- FTI or FT4 - These tests are performed in order to determine the level of the thyroid hormone thyroxine that is in the bloodstream. Specifically, these tests focus on quantifying the small amount of the T4 hormone that is unattached to blood cells.
- Total T4 - This blood test shows the total level of thyroxine in the bloodstream, quantifying both attached and unattached cells.
- Thyroid antibodies test - If an autoimmune disorder such as Grave’s disorder is suspected, this blood test is used to determine whether the body’s immune system is attacking the thyroid gland.
- Thyroglobulin levels - This procedure is typically used in the diagnosis and management of thyroid cancer.
Radioactive Iodine Testing
These tests make use of the unique iodine-absorbing properties of the thyroid gland to measure thyroid function. They are usually only performed on patients who are suspected to be hyperthyroid, or when a preliminary diagnosis of thyroid cancer has been made. They involve ingesting a very small dose of radioactive iodine and viewing its path in the body using advanced imaging techniques.
- Radioactive Iodine Uptake Test - This test is used to help doctors achieve a clearer understanding of the source of your thyroid-related symptoms. It can help them to determine whether you are hyperthyroid and the degree of thyroid hyperactivity. It can also allow doctors a closer look at a nodule or growth on the thyroid gland. Lastly, in patients who have been diagnosed with thyroid cancer, this test can show whether the cancer has spread beyond the thyroid gland.
- Thyroid Scan - In some cases, thyroid scans are performed as part of a radioactive iodine uptake test, but they can also be performed as stand-alone assessments. If it is not done in tandem with a radioactive iodine uptake tests, thyroid scans are usually used to observe and diagnose thyroid nodules or growths.
Other Thyroid Imaging Procedures
If a growth or nodule has been detected on your thyroid, your doctor may choose to order several imaging procedures to get a better look at the abnormal tissue and better determine its origins.
- Ultrasound - This painless, non-invasive imaging procedure will provide doctors with a highly detailed snapshot of your thyroid, allowing them to get a closer look at any suspect growths and nodules. The ultrasound, also known as a sonograph, uses sound waves to produce images of internal organs.
- Computerized tomography - More commonly known as CAT scans or CT scans, this imaging technique relies on the same basic technology that powers standard x-rays, although it is applied in a slightly different way. These images can help doctors get a wider look at the entire neck area, which can sometimes be helpful in diagnosing the size and extent of thyroid cancers and malignant growths.
- Magnetic resonance imaging - This relatively newly developed imaging technique draws on the power of magnetism to produce crystal-clear images of internal organs, tissues, and musculoskeletal structures. This test is typically used only if thyroid growths or tumors are believed to be present.
They say that knowledge is power, and when it comes to medical procedures, having a basic understanding of the nature of the tests that are being performed can make all the difference in the world. If you are unclear about the purpose or nature of any of the diagnostic procedures your doctor has arranged, don’t hesitate to request more information. Remember, the only stupid question is the one that remains unasked!
For Further Reading
Note: The contents of this blog are for informational purposes only and are not intended to be construed as medical advice or as a substitute for professional care. This site should not be used in place of professional medical advice. The author is not a physician. For medical emergencies, call 911!
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