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What Can Affect Thyroid Test Results

Understanding Your Thyroid Test Results

How Biotin Interferes with Thyroid Lab Tests & Causes Falsely Elevated Results

With Cory Rice DO

Healthy TSH levels are usually an indicator that the whole system is working as it should.

Thyroid disorders are complicated, fickle, and highly individual meaning thyroid issues are going to look very different for each person. In any case, its important to have a basic understanding of how the thyroid gland works and the hormones it produces. This understanding can help you advocate for yourself and ask the right questions when you visit your healthcare provider. It can also clue you into some of those mysterious symptoms you may be experiencing.;

An introduction to the thyroid gland

First things first: The thyroid gland is part and parcel of the endocrine system, which is a collection of glands that produce all-important hormones responsible for metabolism, growth, sexual function, sleep, and your mood.;

The gland, which is tiny and butterfly-shaped, is found at the bottom front of your neck. It makes the two main thyroid hormones, triiodothyronine and thyroxine both of which have a major hand in your energy levels, internal temperature, hair, skin, weight, and more. For this reason, T3 and T4 are definitely not to be taken for granted and you probably know this already if youve experienced any of the frustrating symptoms of a thyroid disorder.;

Is Fasting Required For A Thyroid Test

Most doctors will suggest you do not fast before your thyroid function test.

Research shows that fasting, especially early in the morning, may impact TSH levels. A fasting test typically results in higher TSH levels versus one done in the afternoon.

Because fasting causes higher TSH levels, it can make it hard to properly diagnose hypothyroidismwhich is diagnosed specifically by looking at TSH levels.

What Is A Normal Thyroid Level

Tests often used to assess thyroid hormone status include TSH and FT4 tests. The normal value for a laboratory test is determined by measuring the hormone in a large population of healthy individuals and finding the normal reference range. Normal ranges for thyroid tests may vary slightly among different laboratories, and typical ranges for common tests are given below.

TSH normal values are 0.5 to 5.0 mIU/L. Pregnancy, a history of thyroid cancer, history of pituitary gland disease, and older age are some situations when TSH is optimally maintained in different range as guided by an endocrinologist.

FT4 normal values are 0.7 to 1.9ng/dL. Individuals taking medications that modify thyroid hormone metabolism and those with a history of thyroid cancer or pituitary disease may be optimally managed with a different normal FT4 range.

Total T4 and Total T3 levels measure bound and free thyroid hormone in the blood. These levels are influenced by many factors that affect protein levels in the body, including medications, sex hormones, and liver disease. A normal Total T4 level in adults ranges from 5.0 to 12.0g/dL. A normal Total T3 level in adults ranges from 80-220 ng/dL.

Free T3 assays are often unreliable and not routinely used to assess thyroid function.

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How Is Hypothyroidism Treated

To make matters even more confusing, we still do not recommend universal treatment for people who have subclinical hypothyroidism: slightly elevated TSH and normal free T4.

Even though subclinical hypothyroidism is associated with worse health outcomes, treatment with thyroid hormone medicine may not significantly improve a persons symptoms and quality of life.

From my perspective, more lab testing may cause anxiety, generate further tests, and lead to unnecessary treatment, which can cost hundreds, and sometimes thousands, of dollars. We have good solid evidence to support simple tests to diagnose hypothyroidism and follow people who need treatment for it. I recommend questioning any doctors who recommend tests that are not supported by clinical research. While it may sound like a good idea to check more biomarkers, its important to understand the limitations of weak evidence before embarking on this journey. On some of these websites, dollar signs are just a click away.

Factors Affecting Your Thyroid

Thyroid Testing

Your specialist may test over 100 factors influencing the thyroid system including:

  • Iodine concentration
  • Deep Tendon Reflex Relaxation Time
  • Tests Related to Cardiovascular Function

Those factors may or may not be affected by the medications that you take. The endocrine specialist will examine your history, symptoms and medications to properly evaluate you.

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How Is The Tpo Antibodies Test Performed

TPO antibodies test is, basically, a blood test. Your healthcare provider or a lab technician will take a sample of your blood in order to measure how many antibodies are in it.

The blood sample is collected by inserting a needle into a vein in the arm. You might feel a little sting when the needle goes in or out. The whole process lasts five minutes maximum. TPO antibodies test requires no special preparations.

However, you should inform the doctor if you’re taking some medications, supplements, or herbs. Some drugs and supplements may impair the results.

Based on the information you provide, the doctor will suggest whether you can continue taking the medication or supplement even on the day of the test or not.

Follow the doctors recommendations religiously in order to get accurate results and precise diagnosis or insight into your condition.

Thyroid Testing: How It Works

Thyroid tests use a blood sample to measure various hormone levels. Thyroid-stimulating hormone , for example, is often measured to indirectly check if your thyroid gland is producing enough thyroid hormones. TSH levels are usually higher than normal if you have an underactive thyroid .

Thyroid function tests can also measure thyroid hormones like thyroxine to provide a better understanding of how low â or how high â your thyroid hormone levels are.

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How To Test For Thyroid Problems At Home

How to check your thyroid hormones at home?

The Everlywell at-home thyroid test can tell you if your thyroid hormone levels suggest hypothyroidism. This test requires only a few drops of blood as a sample. After getting your online test results, you can easily see your levels of thyroid-stimulating hormone , free T3 and T4, and TPO antibodies. High TSH and/or low T3 and T4 can indicate hypothyroidism.

You can also take our thyroid test at home to check your hormones for indications of hyperthyroidism. Hyperthyroidism means your thyroid gland is overactive: itâs producing too many hormones. Low levels of TSH and/or high T3 and T4 can suggest hyperthyroidism.

Vitamins Could Throw Off Thyroid Lab Test Results

READING A THYROID BLOOD TEST PANEL // WHAT YOUR RESULTS CAN MEAN?

Q. I feel perfectly healthy, but my latest physical showed an abnormal thyroid lab test. I take a handful of vitamins, no drugs, and I don’t want to start any now. My doctor wants me to begin prescription thyroid hormone. Should I get a second opinion?

–K.S., Pueblo, Colo.

A. That’s up to you, but before you get a second opinion, you may want to repeat the lab work minus the “handful of vitamins.” Many natural over-the-counter supplements can affect lab work related to numerous functions, including your thyroid gland.

Natural estrogens such as soy can elevate thyroid-stimulating hormone. Tyrosine, an ordinary amino acid, happens to be a thyroxine precursor, meaning it could lower a person’s TSH. Tyrosine is taken for many conditions, including depression; it’s found in protein shakes.

Other problematic supplements include biotin, kelp and bladderwrack. You don’t have to stop taking these; you just need to know that they may throw off otherwise normal thyroid lab tests. This is important information because the last thing you want to do is take medicine for a condition that does not truly exist.

Why don’t you go on a vitamin holiday? Stop taking everything for a week, then retake your lab tests.

Q. I take a diuretic, furosemide , for my high blood pressure, but now my potassium also is low. Before I begin a prescription dose of potassium, I was wondering if certain foods might help my situation. I’ll eat anything.

–L.L., Chicago

–G.D., Hollywood, Fla.

Did you know?

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Caffeine Alcohol And Tobacco

Drinking a lot of caffeine from coffee or green tea can also affect some blood test results. Although more studies are necessary when it comes to caffeine, there is a chance that this substance can alter blood glucose levels and temporarily increase them. Caffeine usually passes through the body in around 5 hours, so its effects are less significant in comparison with other substances. Caffeine can also affect hydration, a factor mentioned above. Last but not least, caffeine can increase blood pressure in some people. The lab technician may be alarmed about your blood pressure before drawing your blood.

Alcohol, on the other hand, has a more significant effect on blood tests, depending on how much is consumed and when. For example, this substance might lower serum glucose levels in people of all ages and increase plasma lactate. These changes can happen, especially if alcohol is consumed 2 or 4 hours before drawing blood for testing.

At the same time, chronic alcohol consumption can lead to other problems such as elevated triglyceride levels, elevated creatine kinase levels, elevated liver enzymes, and increased uric acid. As a result, blood tests can be affected, and the doctor could subsequently give a false diagnosis.

As a result, blood tests can come up with confusing results. Whether cigarette smoking is acute or chronic, its detrimental for ones health, and it can mess up with lab investigations.

How Are Thyroid Tests Done

In order to properly test the hormone levels of your thyroid, a blood draw will be performed by your doctor or at a lab.

Prior to the blood draw, you will be asked to sit in a chair, roll up your sleeves and relax while a nurse or technician prepares your arm for the draw.

A band of rubber will be tightly tied around your upper arm to force the veins to swell. This makes it easier for a vein to be found so the needle can be inserted.

Having blood drawn is mostly painless, although it is possible to feel a sharp prick when the needle is inserted. This is typically a very quick sensation.

Once the blood has been fully drawn, the needle will be removed and a small bandage will be placed over your wound.

Before your tests are performed, you should tell your doctor if youre taking any medication or if you may be pregnant. This may alter the results of your test.

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How To Test Your Thyroid Function

You can test your thyroid function using a blood sample. The two main ways to collect a blood sample are:

  • a venous blood test a trained professional will use a needle to puncture a vein, usually in your arm, to collect a blood sample.
  • a finger-prick blood test using a lancet, you can prick your own finger and collect a small blood sample.

What Are Thyroid Hormones

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The thyroid gland produces hormones that are essential for normal body metabolism. Blood testing is now commonly available to determine the adequacy of the levels of thyroid hormones. These blood tests can define whether the thyroid gland’s hormone production is normal, overactive, or underactive.

The thyroid gland is located in the lower part of the neck, below the Adam’s apple.The gland wraps around the windpipe and has a shape that is similar to a butterfly – formed by two wings and attached by a middle part .

The thyroid gland uses iodine to produce thyroid hormones.

  • The two most important thyroid hormones are thyroxine and triiodothyronine , which account for 99.9% and 0.1% of thyroid hormones present in the blood respectively.
  • However, the hormone with the most biological activity is T3.
  • Once released from the thyroid gland into the blood, a large amount of T4 is converted into T3 – the active hormone that affects the metabolism of cells.

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Thyroid Function Test Results Explained

The thyroid usually changes slowly. It hardly ever quickly changes to being overactive or underactive: it usually takes a few weeks at least, or even a few months. If you have a thyroid function test that shows something is wrong, it’s usually worth repeating it in 3-6 weeks. That is because there’s always the chance that your thyroid gland could have gone back to normal by itself.

The second thing to bear in mind about thyroid function tests is that medications, and even herbal remedies or vitamin supplements, can affect the accuracy of thyroid results.

For these two reasons it’s always recommended to have a thyroid function test if it is recommended to you by a doctor, rather than having it done privately or without a doctor suggesting it.

Side Effects And Aftercare

A blood draw is a routine, minimally invasive procedure. During the days immediately after the blood draw, you may notice slight bruising or soreness at the area where the needle was inserted. An ice pack or an over-the-counter pain reliever can help ease your discomfort.

If you experience a great deal of pain, or if the area around the puncture becomes red and swollen, follow up with your doctor immediately. These could be signs of an infection.

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Why Do I Need A Tsh Test

You may need a TSH test if you have symptoms of too much thyroid hormone in your blood , or too little thyroid hormone .

Symptoms of hyperthyroidism, also known as overactive thyroid, include:

Symptoms of hypothyroidism, also known as underactive thyroid, include:

  • Weight gain
  • Low tolerance for cold temperatures
  • Irregular menstrual periods
  • Constipation

Different Types Of Autoimmune Thyroid Disease

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Falk: What on earth is autoimmune thyroid disease?

Kirk: Autoimmune thyroid disease is a complex term. Its not really one disease. Its rather a term that refers to a number of different ways that the immune system could affect the thyroid gland.

Falk: Where is the thyroid?

Kirk: The thyroid is on the base of the neck in the midline, so if you were to take your fingers and press right at the bottom of the neck, you probably wouldnt feel it because most thyroid glands are difficult to feel. Its about 4 centimeters tall on either sideits the shape of a butterfly, we like to say. Thats where its located.

Falk: So that organwhat is the thyroid supposed to do in the first place?

Kirk: The thyroid does a lot of things. It produces thyroid hormones. These hormones affect essentially every cell in the body. A simple way to think about what thyroid hormone does, is it is a contributor to metabolism and activity so it may rev up the system, so to speak. If its produced in appropriate quantities it keeps many organs and systems in equilibrium.

Falk: So if your thyroid is overworking or hyperactive, how do you feel?

Kirk: If your thyroid is overactive or if youre producing too much thyroid hormone you may lose weight without meaning to, you may be very hot, you may be sweaty, anxious, or have tremors that you or others may notice. We often hear people say that they have rapid heartbeat or fluttering sensation which we refer to as palpitations.

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Thyroid Hormone Resistance And Also Disorder Of Thyroid Hormone Transport Or Metabolism

These are conditions that are rare and very difficult to diagnose properly.;In these conditions sometimes because of genetic variation your body might become resistant to thyroid hormone.;This is similar to what we see in Type II Diabetes where the body becomes resistant to the lin hormone.

The second condition is where there is a problem with either too high levels of thyroid binding protein or low levels of thyroid-binding protein.;The thyroid hormone in the bloodstream is present in the bound form.;Thyroid hormone is bound to thyroid binding protein, so if there is a significant difference in the levels of these thyroid-binding proteins it can interfere with optimal levels.;Some of this condition is attributable to high cortisol levels and also is estrogen levels .;;

Thyroid Peroxidase Antibodies Test And Who Needs It

Thyroid peroxidase antibodies test measures the level of an antibody that is directed against TPO.

These antibodies are produced in the body by the immune system, as mentioned above.

The TPO antibodies test serves multiple purposes, such as:

  • Helping doctors diagnose autoimmune thyroid disorders
  • Aiding in differentiating autoimmune thyroid disorders from non-autoimmune hypothyroidism or goiter
  • Serves as a diagnostic tool in deciding whether to treat a patient who has been diagnosed with subclinical hypothyroidism

Doctors may also order a TPO antibodies test if you are pregnant and have an autoimmune disease, particularly the condition that involves thyroid.

Thyroid peroxidase antibodies have been associated with reproductive difficulties such as miscarriage, preeclampsia, premature delivery, and in-vitro fertilization failure. In these instances, the doctor may also order TPOAbs test, but bear in mind its not a standard test for problems with fertility and pregnancy.

If a pregnant woman has an autoimmune thyroid condition or some other autoimmune disease with thyroid involvement, the doctor may order TPO antibodies test in order to determine whether the baby could be at risk of thyroid dysfunction.

Additionally, you might need a TPO antibodies test if other thyroid hormone levels are too low or too high. Your doctor will need results from TPO antibodies test to determine whether an autoimmune condition impaired the production and concentration of thyroid hormones.

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Can I Take The Test At Home

Several test kits are commercially available that allow you to provide a sample for TSH testing at home. Some kits test only TSH, and others test TSH in combination with other thyroid hormones or additional hormones, such as cortisol and free testosterone.

These kits may be purchased online and include the materials you need to take a finger prick sample of blood and return it to the company for testing. Your test results will be reported to you via a secure online platform.

At-home testing is convenient and can help you participate in your health care. But at-home tests cannot replace working with a health care provider. If you have symptoms or are concerned that your thyroid is not functioning properly, be sure to share your concerns with your doctor. If an at-home test detects an abnormal TSH level, your doctor is likely to retest the TSH and follow-up with additional testing if the second TSH test is also abnormal.

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