Tsh Levels: Normal High Or Low
Jenny Hills, Nutritionist and Medical Writer Health
TSH is a hormone secreted by the brains pituitary gland to control the activity of your thyroid gland. TSH stands for thyroid stimulating hormone and as its name suggests, it stimulates the thyroid to produce thyroid hormones. Levels of TSH affect the production the hormones triiodothyronine and thyroxine . Doctors usually test TSH level to see if its within the normal range if you show symptoms of an overactive or underactive thyroid.
You may also have to regularly go for a TSH blood test or T4 blood test if you are receiving hormone treatment for a thyroid condition.
Optimal TSH levels are critical for your bodys function, including your general health and wellbeing. Thyroid hormones help control your metabolic rate, heart function, nervous system, and digestion. Although TSH isnt classed as a thyroid hormone, high or low TSH levels can disrupt levels of T3 and T4. This can result in symptoms of hyperthyroidism or hypothyroidism.
In this article, you will find out all you need to know about TSH and how it affects your thyroid hormone levels. You will also learn about thyroid-related symptoms if TSH levels are higher or lower than the normal range.
T3 And T4 Test Results
If your TSH levels are off, your provider will most likely check your T4 levels and T3 levels. If one or both of these come back elevated, along with a low TSH, it usually indicates hyperthyroidism. If they are low, it can indicate hypothyroidism. Further testing would be necessary to find the cause.
How Is Hyperthyroidism Diagnosed
If your physician suspects that you have hyperthyroidism, diagnosis is usually a simple matter. A physical examination usually detects an enlarged thyroid gland and a rapid pulse. The physician will also look for moist, smooth skin and a tremor of your fingers. Your reflexes are likely to be fast, and your eyes may have some abnormalities if you have Graves disease.
The diagnosis of hyperthyroidism will be confirmed by laboratory tests that measure the amount of thyroid hormones thyroxine and triiodothyronine and thyroid-stimulating hormone in your blood. A high level of thyroid hormone in the blood plus a low level of TSH is common with an overactive thyroid gland. If blood tests show that your thyroid is overactive, your doctor may want to measure levels of thyrotropin receptor antibodies , which when elevated confirm the diagnosis of Graves disease. Your doctor may also want to obtain a picture of your thyroid . The scan will find out if your entire thyroid gland is overactive or whether you have a toxic nodular goiter or thyroiditis . A test that measures the ability of the gland to collect iodine may be done at the same time.
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In People Being Treated For Thyroid Disease
A high TSH may be found in people being treated for either hypo- or hyperthyroidism.
With hypothyroidism, a high TSH usually means that the dose of thyroid hormone replacement needs to be increased.
In some cases, however, the dose is okay, but the medication is not being fully absorbed. For example, many foods and medications can affect the absorption of Synthroid in your system. Learning what to avoid while taking this medication is important for it to work properly.
With hyperthyroidism, a high TSH usually means that the treatmentbe it surgery, radioactive iodine, or medicationswas so effective in limiting the production of thyroid hormone that it caused the person to become hypothyroid.
A low TSH often means that a person has an elevated level of thyroid hormones.
Tsh Levels For Children
The Journal of Clinical Endocrinology & Metabolism says that the normal TSH range for children that take into account their age is as follows:
- Infants 1 day old: 1.9 17.58 mIU/L
- Infants 1 week old: 0.58 5.57 mIU/L
- Children one-year-old: 0.57 5.54 mIU/L
- Adolescents 18 years old: 0.51 4.93 mIU/L
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How Do You Test Tsh Levels
Healthcare providers test TSH levels using a blood test. They take a sample of blood from a vein in your arm and send the sample to a laboratory for testing. You usually dont need to do anything special to prepare for a TSH blood test.
A TSH blood test is usually the first test providers order if youre experiencing symptoms related to thyroid issues.
How Does Subclinical Hypothyroidism Develop
The way that subclinical hypothyroidism develops depends on a number of different factors including the TSH level: Slightly elevated TSH levels often return to normal on their own. But people who have highly elevated levels often develop symptomatic overt hypothyroidism within several months or years.
One study followed people with high levels of TSH over a period of two to three years. The participants didn’t have any symptoms or diagnosed thyroid disorders. They were divided into three groups depending on how high their TSH levels were. The study produced the following results:
- Slightly elevated TSH levels : Each year, 2% of the participants in this group developed overt hypothyroidism.
- Moderately elevated TSH levels : Each year, 20% of the participants in this group developed hypothyroidism with symptoms.
- Highly elevated TSH levels : Each year, 73% of the participants in this group developed overt hypothyroidism.
TSH levels that are slightly or only moderately elevated don’t necessarily need to be treated. Some people who have high TSH levels never even develop symptoms. It is also very common for TSH levels to return to normal in children and teenagers.
The probability that overt hypothyroidism develops from subclinical hypothyroidism is greater if the thyorid is enlarged and thyroid antibodies are detectable in the blood. And women generally have a higher risk than men.
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Is There Anything Else I Need To Know About A Tsh Test
TSH levels may be high or low even when your thyroid gland is healthy. Serious illnesses not related to your thyroid may cause lower TSH levels for a short time. And TSH levels may be higher in people over age 80, even though they don’t have any thyroid problems.
Pregnancy also affects TSH levels. They are often a little low during the first three months. But sometimes, thyroid disease develops during pregnancy. If you develop thyroid disease during pregnancy, your provider will monitor your condition through your pregnancy and after your baby is born. That’s because hyperthyroidism, and less often, hypothyroidism, can continue after you give birth. If you have a history of thyroid disease, be sure to talk with your provider if you are pregnant or are thinking of becoming pregnant.
Newborn babies are routinely screened with a TSH test to see if they were born with hypothyroidism .
What Are The Treatments For Hyperthyroidism
The treatments for hyperthyroidism include medicines, radioiodine therapy, and thyroid surgery:
- Medicines for hyperthyroidism include
- Antithyroid medicines, which cause your thyroid to make less thyroid hormone. You probably need to take the medicines for 1 to 2 years. In some cases, you might need to take the medicines for several years. This is the simplest treatment, but it is often not a permanent cure.
- Beta blocker medicines, which can reduce symptoms such as tremors, rapid heartbeat, and nervousness. They work quickly and can help you feel better until other treatments take effect.
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In People With Thyroid Disease
In people being treated for hypothyroidism, a low TSH level may mean:
- Overmedication with thyroid hormone replacement
- Interactions that cause increased absorption or activity despite an optimal dose of medication
- Central hypothyroidism
In people being treated for hyperthyroidism, a low TSH level usually means that further treatment is needed to reduce thyroid hormone levels.
It could also mean that a person must continue to be monitored to make sure thyroid hormone levels return to normal. This is often the case for people who have temporary thyroiditis related to pregnancy or chemotherapy treatment.
Treatment may be more aggressive than needed
Medication may be absorbing too much
Are There Complications Of Hyperthyroidism
Thyroid storm is a rare but serious complication of hyperthyroidism. It happens when your thyroid makes and releases a large amount of thyroid hormone in a short amount of time. Thyroid storm is a life-threatening emergency that requires immediate medical attention.
Symptoms of thyroid storm include:
- High fever a temperature between 104 degrees to 106 degrees Fahrenheit is common.
- Rapid heart rate that can exceed 140 beats per minute.
- Feeling agitated, irritable and/or anxious.
- Congestive heart failure.
- Loss of consciousness.
A complication of Graves disease, one of the causes of hyperthyroidism, is called Graves eye disease . This condition can usually not be prevented. Graves eye disease can cause the following complications:
- Bulging eyes.
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What Happens When Tsh Levels Are Too Low
If you have too little TSH, its most likely that your thyroid gland is making excess thyroid hormone. This condition is called hyperthyroidism, or overactive thyroid. A variety of conditions lead to hyperthyroidism, including Graves’ disease and thyroid nodules. A little over 1% of adults in the United States have hyperthyroidism.
Since thyroid hormone suppresses TSH release, high levels of thyroid hormone can cause lower-than-normal TSH levels. Rarely, issues with your pituitary gland, such as a non-functioning pituitary adenoma, can result in low TSH levels as well as low thyroid hormone levels.
Symptoms of low TSH levels
Low TSH levels are usually a sign of hyperthyroidism. Symptoms of hyperthyroidism include:
If youre experiencing these symptoms, its important to talk to your healthcare provider. Hyperthyroidism is treatable.
Symptoms Of A Thyroid Issue
What are the symptoms of a thyroid problem? The symptoms of a thyroid problem comes from hyperthyroidism or hypothyroidism, both caused by unbalanced thyroid levels. Thyroid disease symptoms include:
- Enlarged thyroid
- Eye problems
Graves disease or Hashimotos thyroiditis can lead to dangerously high or dangerously low thyroid hormone levels, respectively. There are many triggers for Graves or Hashimotos.
Its crucial to know if a patients thyroid imbalance is due to Hashimotos or Graves disease these are autoimmune conditions with a significantly different root cause and treatment strategy than thyroid disease which is not autoimmune in nature.
Testing For T3 T4 And Tsh Levels
Here at PrimeHealth, we administer a more robust set of thyroid function tests than most of the medical community. Many conventional primary care doctors and endocrinologists tend to only focus on TSH levels.
Additionally, its important to take into account optimal levels versus reference range levels. Thats why we administer a more thorough panel of tests.
Also, keep in mind that if youre taking thyroid medications, the time from your last dose will change the way we interpret your lab values. Your provider may have you test your thyroid panel before or after taking your medication in the morning to assess your thyroid levels at various times during the day.
We believe the most accurate and thorough way to test for thyroid function is to measure:
- Anti-thyroglobulin and anti-TPO antibodies
- Thyroid-binding globulin
Important: Make sure youre not taking biotin when testing for thyroid hormone levels. This popular supplement for hair and nail growth can interfere with test results.
What are normal TSH test results? The normal range of thyroid test results is 0.5-5.0 mIU/L, but we recommend TSH levels stay under 2.5 mIU/L. If your TSH level sits outside this reference range, you probably suffer from a thyroid disorder that needs to be treated.
Hypothyroidism Tests: A Measure Of Treatment Success
Hypothyroidism is treated with daily medication. Taking synthetic thyroid hormone medication can bring your T4 and TSH levels back to their normal ranges. Once youre on the right dose, your symptoms should subside.
When you first start taking medication, your doctor will need to monitor your blood to fine-tune the dosage. Initially you will need to be tested more frequently, Doria-Medina says. A person who is newly diagnosed and taking medication for hypothyroidism should be tested every six weeks until the dosage is just right.
The dose you start with is your doctors educated guess about whats best for you most likely the lowest dose possible to avoid side effects, which can include a rapid heartbeat and restlessness.
Medication for hypothyroidism is slow acting, and it can take several weeks for your body to adjust. If your TSH is still high and your symptoms havent subsided after 6 to 10 weeks, your doctor will likely increase the dose, and youll need your blood tested again after another 6 to 10 weeks.
Will I Need To Do Anything To Prepare For The Test
In most cases, you don’t need any special preparations for a thyroxine blood test. Certain medicines and supplements may affect your test results, so let your provider know what you’re taking, but don’t stop any medicines without talking with your provider.
If your provider has ordered more tests on your blood sample, you may need to fast for several hours before the test. Your health care provider will let you know if there are any special instructions to follow.
Hyperthyroidism Signs And Symptoms
- Fine, brittle hair
- Changes in your menstrual cycle
If youâre an older adult, youâre more likely to have subtle symptoms like a faster heart rate or being more sensitive to warm temperatures. Or you could just feel more tired after everyday activities.
Certain medicines can mask the signs of hyperthyroidism. If you take beta-blockers to treat high blood pressure or another condition, you might not know you have it. Be sure your doctor knows about all the medications you take.
When you first get hyperthyroidism, you may feel energetic. This is because your metabolism is sped up. But over time, this increase in your metabolism can break your body down and cause you to feel tired.
Usually, hyperthyroidism develops slowly. If youâre young when you get it, the symptoms might come on suddenly.
To Treat Or Not To Treat
Aging WellVol. 5 No. 6 P. 6
Physicians are accustomed to checking thyroid-stimulating hormone in older adults with symptoms of an over- or underactive thyroid, as its a fairly accurate and routine measure of thyroid function. But a new study suggests that for many patients, treatment for mild TSH elevations may no longer be warranted.
As increasing numbers of people live into their 80s and 90s, it is important to know how to manage their health, including thyroid function, says Anne Cappola, MD, ScM, an associate professor of medicine at the Perelman School of Medicine at the University of Pennsylvania and lead study author. We sought to describe what happens to thyroid function in older people over time and to determine the relationship between thyroid function and mortality in this population.
The study, accepted for publication in The Endocrine Societys Journal of Clinical Endocrinology & Metabolism, questions the assertion that slightly elevated TSH levels are linked to an increase in mortality and suggests that such elevations may actually be a normal part of healthful aging.
Study Particulars The study first examined 5,888 men and women aged 65 and older between 1989 and 1992. Then in 2005, researchers reexamined 843 surviving participants thyroid function for any changes in physical and cognitive function. Study participants ranged in age from 77 to 102, with a mean age of 85.
Juliann Schaeffer is an associate editor at Great Valley Publishing Company.
How Is Hypothyroidism Diagnosed
Your health care provider may use many tools to make a diagnosis:
- A medical history, including asking about your symptoms
- A physical exam
- Imaging tests, such as a thyroid scan, ultrasound, or radioactive iodine uptake test. A radioactive iodine uptake test measures how much radioactive iodine your thyroid takes up from your blood after you swallow a small amount of it.
What Are T3 And Ft3
Triiodothyronine is usually referred to as T3 and is one of the hormones that the thyroid secretes. Doctors from the American Association for Clinical Chemistry say that T3 is more active than the more abundant T4 and is a powerful thyroid hormone in the body. Free T3 is the amount of triiodothyronine that is not bound to protein and can still be used by the body. Doctors sometimes run tests for total T3 or just FT3 to check thyroid function.3
Are There Any Risks To Hyperthyroidism Treatments
With most treatments, there are also risks of side effects. Its important to talk to your healthcare provider and weigh all of the advantages and disadvantages before deciding on a treatment plan. Some of these risks include:
After treatment, youll most likely need to take replacement thyroid hormone for the rest of your life. This is because some of these treatments especially surgery reduce your thyroid hormone levels to very low levels or eliminate this hormone by removing your thyroid. Youll need to reintroduce the thyroid hormones back into your system by taking regular medication.