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Can Thyroid Blood Test Be Wrong

Thyroxine Triiodothyronine And Tsh Levels

Can Thyroid Tests Be Wrong ? [ 2021 ]

The main job of the thyroid gland is to make the hormone thyroxine, also known as T4 because it has four iodine molecules. The thyroid also makes the hormone triiodothyronine, known as T3 because it has three iodine molecules, but in smaller amounts, explains Cathy Doria-Medina, MD, an endocrinologist with HealthCare Partners Medical Group in Torrance, California. The thyroid gland makes mostly T4, the T4 has to be converted to T3, because T3 is the part of thyroxine that actually does the work, she says.

The pituitary gland at the base of the brain controls hormone production in your body. It makes thyroid-stimulating hormone , which tells the thyroid gland how much T4 and T3 to produce. The TSH level in your blood reveals how much T4 your pituitary gland is asking your thyroid gland to make. If your TSH levels are abnormally high, it could mean you have an underactive thyroid, or hypothyroidism. Thats because it indicates your pituitary gland is producing more TSH in an effort to stimulate your thyroid to produce thyroid hormone, according to the Mayo Clinic.

TSH levels go in the opposite direction of your thyroid hormone, Dr. Doria-Medina explains. If youre making too little thyroid hormone, your TSH will go up. If youre making too much thyroid hormone, your TSH will go down.

If your TSH is higher than 4.0 mU/L on repeat tests, you probably have hypothyroidism.

Read Also: How To Stop Thyroid Hair Fall

Why Do I Still Have Hypothyroid Symptoms With Normal Labs

Medically reviewed by Dr. Yasmin Akhunji, MD
  • What is normal thyroid function?
  • Thyroid function tests
  • Common thyroid function patterns
  • Other factors that may contribute to your symptoms

In medicine, an accurate diagnosis is critical to determine the most effective course of treatment. Often, when a patient gets back normal thyroid test results, but they still experience hypothyroid symptoms, they’re left wondering what’s wrong and what to do next.

Ahead, a look at each thyroid biomarker, how to interpret thyroid function patterns, and what to do if you still experience hypothyroid symptoms with normal labs.

What Might Tamper With Test Results

  • The time of the day and seasonTSH is not produced by the thyroid at the equal rate during the entire day. It follows a circadian rhythm and is mostly produced during your sleep. Currently, a normal reference range of serum TSH for adults is 0.44.5mIU/L. In some countries that upper limit has been disputed, and reduced to 2.5mIU/L .
  • Type of the test used
  • Eating too little or overeatingIf you are under nourished you might experience the decrease in fT3 and total T3. Overeating will have an opposite effect and increase fT3 and T3.
  • StressStress is a big factor in thyroid health and it decreases T3.
  • Certain medicationsMedications can increase fT3 and fT4, but not in a good way. These medications block the activity of T3 and T4, so it doesnt matter if theres more T3 and T4 found in the blood as theyre unable to fulfil their functions.
  • ExerciseIf youve recently did any type of long, excessive, or high-intensity exercise, you should a couple of days before going to be tested. In general its not good not to overexercise if you have a thyroid condition.
  • Sometimes labs make mistakesThis doesnt happen often, but people make mistakes. Sometimes the chemicals used for testing might be old or spoiled. Usually people in the lab realize this quickly and can re-test with the same blood sample and freshly prepared chemicals.

Recommended Reading: Can You Have Normal Thyroid Levels And Still Have Hypothyroidism

How Does This Happen

Thyroid physiology is complex. Most conventional doctors use only a standard test for thyroid function which includes only TSH and T4. But this standard test only picks up a small percentage of thyroid disorders, unfortunately.

Normally when the body cannot supply enough usable thyroid hormone for it to function properly, the Thyroid Stimulating Hormone increases in an effort to get the thyroid to make more thyroid hormone. Many thyroid problems, however, exist even if TSH shows as normal. This is more common than you may realize.

Just what is considered normal on a thyroid test? Ranges for normal vary from lab to lab, and from one doctors interpretation to another doctors. Lab ranges are not based on research that tells us a true optimal range, but on a bell curve of values obtained from people who come to the labs for testing, many of whom may have thyroid problems. So thats the starting point for thyroid readings. They just arent looked at within an optimal lab range context.

That brings us to another problem with the TSH standard thyroid test.

Your body creates two primary thyroid hormonesT3 and T4. About 94 percent of the hormone made in the thyroid gland is T4. The remaining 6 % is T3, named for its three molecules of iodine.

It is necessary to get a more thorough thyroid test called a complete thyroid panel that will look at T3 and T4 levels and other essential components of thyroid function.

What Does The Thyroid Do

Thyroid Blood Work

Your thyroid has an important job to do within your body releasing and controlling thyroid hormones that control metabolism. Metabolism is a process where the food you take into your body is transformed into energy. This energy is used throughout your entire body to keep many of your bodys systems working correctly. Think of your metabolism as a generator. It takes in raw energy and uses it to power something bigger.

The thyroid controls your metabolism with a few specific hormones T4 and T3 . These two hormones are created by the thyroid and they tell the bodys cells how much energy to use. When your thyroid works properly, it will maintain the right amount of hormones to keep your metabolism working at the right rate. As the hormones are used, the thyroid creates replacements.

This is all supervised by something called the pituitary gland. Located in the center of the skull, below your brain, the pituitary gland monitors and controls the amount of thyroid hormones in your bloodstream. When the pituitary gland senses a lack of thyroid hormones or a high level of hormones in your body, it will adjust the amounts with its own hormone. This hormone is called thyroid stimulating hormone . The TSH will be sent to the thyroid and it will tell the thyroid what needs to be done to get the body back to normal.

Read Also: How To Stop Thyroid Hair Fall

Blood Levels Of Thyroid Hormone Are Not Necessarily What We Care About

This is another huge problem so let me explain…

I explain it this way to my patients:

The bloodstream in your body is just a way to move nutrients and hormones to the places that actually need it.;

Your tissues and organs.

The amount of thyroid hormone in the blood is only helpful to us if we KNOW for sure that the hormone and nutrients are making it into your cells.

Most doctors check your blood levels of hormones and assume that if blood levels are “normal” that your tissues must be getting the right amount of hormone.

But, obviously, that isn’t the case.

What’s more important than your blood levels of thyroid hormone is the answer to this question:

Are your tissues actually getting the right amount of thyroid hormone?

And we are somewhat limited in how we can actually test this, short of doing a biopsy at the target tissue and it certainly doesn’t make sense to biopsy muscle, heart tissue or brain tissue to diagnose your hypothyroidism.

Instead, we can use a couple of surrogate markers to evaluate if your tissues are getting enough thyroid hormone:

  • Your basal body temperature;- This can give us an idea of what kind of total energy your body is producing. If your temperature is low, you may have a problem getting thyroid hormone into your cells. You can read more about how to test your basal body temperature and how to follow this value while taking thyroid medication here.;
  • The Myth Of Blood Tests As The Only Reliable Way Of Diagnosing Thyroid Conditions

    If your TSH test result is abnormal the lab will run an FT4 check as well.; Whilst this is an improvement on a TSH only check, it is still fallible and can produce false negatives.

    Doctors have been looking for a diagnostic test for thyroid problems ever since the importance of thyroid hormones was recognised late in the eighteenth century.; There have been numerous proposals for different tests for thyroid illness prior to the advent of the blood test used today but not one was found to be reliable. ;Unfortunately, the currently used thyroid function test, based on a blood sample, has its own limitations.

    What should really be measured are the thyroid hormone levels in every cell in the body. ;As it is not practical to do this, they are in effect inferred from those in the bloodstream. ;However, the transfer of thyroid hormones from the bloodstream and into the cells is quite a complicated matter and there are several points in the process where problems may arise.

    If your clinician dismisses your symptoms as being too general and non-specific Non-specific “have more than one possible cause” to allow a definitive diagnosis to be made from them, your hypothyroidism may well remain undiagnosed. ;Ideally non-thyroidal blood markers indicating thyroid hormone insufficiency should be identified and these would be more informative.

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    Why Routine Blood Tests Often Fail To Detect Low Thyroid Function

    All too often the routine blood tests fail to detect a significant percentage of low thyroid cases. Frequently sick patients are told their labs are normal, with values falling within reference ranges, yet they are suffering. Symptoms can be debilitating and may include depression, anxiety, unexplained weight gain, severe fatigue, hair loss, brain fog, constipation and sleep issues. Women often have menstrual cycle irregularities and trouble getting or staying pregnant. I see it every day. It’s unfortunately common and estimated that half of all thyroid disorders may be undiagnosed, leaving patients to suffer without treatment options.

    The lab range used for routine testing has been a controversial topic in medicine in recent years. There is much debate and arguing as to what the actual range should be and what normal is. I began to examine this issue in the ’90s in response to seeing literally hundreds of patients with thyroid-type symptoms and all with normal test results.

    First some background: The thyroid is a small butterfly-shaped gland located at the front of the neck just under the voice box. It produces hormones T4 and T3 responsible for driving energy production and metabolism in every cell in the body. Having the right amount is critical to good health and imbalances can manifest in many different ways depending on which tissue is affected.

    More problems with standard testing…

    TRH — Shining a light on undiagnosed low thyroid.

    Why Your Thyroid Test Results Arent Accurate

    Why Your Doctor Is Wrong About Thyroid Testing

    It wouldnt be an understatement to call thyroid disorders a growing epidemic. The American Thyroid Association conservatively estimates that as many as 20 million people have some form of thyroid disease, and 60 percent of people may be unaware of their condition.1

    Why? The long list of symptoms below could also be symptoms of many other conditions.

    To make matters worse, the cause of thyroid problems in the medical community is largely unknown, according to the ATA. But this doesnt change the fact that more than 12 percent of the U.S. population will develop some kind of thyroid condition within their lifetime. We also know that women are five to eight times more likely to have thyroid problems than men.

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    What Is Being Tested

    Thyroid autoantibodies are antibodies that develop when a persons immune system mistakenly targets components of the thyroid gland or thyroid proteins, leading to chronic inflammation of the thyroid , tissue damage, and/or disruption of thyroid function. Laboratory tests detect the presence and measure the quantity of specific thyroid autoantibodies in the blood.

    The thyroid is a small, butterfly-shaped gland that

    Thyroid autoantibodies are antibodies that develop when a persons immune system mistakenly targets components of the thyroid gland or thyroid proteins, leading to chronic inflammation of the thyroid , tissue damage, and/or disruption of thyroid function. Laboratory tests detect the presence and measure the quantity of specific thyroid autoantibodies in the blood.

    The thyroid is a small, butterfly-shaped gland that lies flat against the windpipe in the throat. The primary hormones that it produces, thyroxine and triiodothyronine , are vital in helping to regulate the rate at which the body uses energy . The body uses a feedback system;in which thyroid stimulating hormone stimulates the thyroid to produce T4 and T3 as needed. This system helps maintain a relatively stable amount of the thyroid hormones in the blood. When thyroid antibodies interfere with this process, they can lead to chronic conditions and autoimmune disorders associated with hypothyroidism or hyperthyroidism, such as Graves disease or Hashimoto thyroiditis.

    Thyroid antibody tests include:

    Five Thyroid Patterns That Wont Show Up On Standard Lab Tests

    In medicine, accurate diagnosis is essential for selecting the most effective course of treatment for a patient. Unfortunately, misdiagnosis is commonplace in the management of hypothyroidism. Countless patients with hypothyroid symptoms are dismissed because their lab values dont fit within the narrow diagnostic criteria established by standard thyroid panels; others are given prescriptions for thyroid hormone replacement, a blanket approach that fails to address the underlying causes of hypothyroidism. Many of these patients suffer from patterns of thyroid dysfunction that dont show up on standard lab tests and that are unfamiliar to conventional doctors. Read on to learn about the five patterns of thyroid dysfunction that are missed by standard lab tests and how you can successfully correct these patterns and restore thyroid health in your patients.

    Recommended Reading: Can A Thyroid Grow Back After Being Removed

    Consider Other Levothyroxine Brands

    Levothyroxine is the generic name of the drug marketed under many different brand names. The majority of people first starting treatment will be prescribed the Synthroid brand. Other available brands include Levoxyl, Levothroid, and Unithroid.

    While the U.S. Food and Drug Administration tightly regulates the type, purity, and amount of key active and inactive ingredients in a drug, different manufacturers may use different fillers and binding ingredients, some of which may affect drug absorption or trigger adverse symptoms. Changing brands may potentially alleviate unintended side effects. Talk to your doctor about whether this might be right for you.

    Hypothyroidism Tests: A Measure Of Treatment Success

    What Blood Test For Thyroid Gland Function and Cancer ...

    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.

    Read Also: How Long For Np Thyroid To Work

    Recommended Reading: How Long Do Thyroid Supplements Take To Work

    The Big Problem With Thyroid Test Results

    Thyroid tests currently dont honor the Body Ecology Principle of Uniqueness. Youre unique, and your own thyroid hormone levels are not like anyone elses. Thyroid tests wont give you an accurate indication of your ideal thyroid hormone level, simply because theyre missing a critical piece of information your peak thyroid level when you were young and healthy.

    Think Twice Before Prescribing Thyroid Hormone

    These five patterns of thyroid dysfunction not only fail to show up on lab work but also tend to respond poorly to conventional thyroid hormone replacement. If a patient cant convert T4 to T3, has high or low levels of TBG, or has cells that are resistant to thyroid hormone, then it doesnt matter how much T4 he takes because his body cant properly use it.

    Rather than merely prescribing thyroid hormone replacement to patients with hypothyroid symptoms, we need to identify and address the underlying causes specific to each pattern. Selecting appropriate lab tests is crucial for piecing together the factors contributing to a patients thyroid dysfunction.

    Read Also: Can Thyroid Cancer Lead To Ovarian Cancer

    Can I Check My Thyroid At Home

    You can do a quick and easy self-exam of your thyroid at home. The only tools you need to do this self-exam are a mirror and a glass of water.

    To do the thyroid self-exam, follow these steps:

    • Start by identifying where your thyroid is located. Generally, youll find the thyroid on the front of your neck, between your collar bone and Adams apple. In men, the Adams apple is much easier to see. For women, its usually easiest to look from the collar bone up.
    • Tip your head back while looking in a mirror. Look at your neck and try to hone in on the space you will be looking once you start the exam.
    • Once youre ready, take a drink of water while your head is tilted back. Watch your thyroid as you swallow. During this test, youre looking for lumps or bumps. You may be able to see them when you swallow the water.

    Repeat this test a few times to get a good look at your thyroid. If you see any lumps or bumps, reach out to your healthcare provider.


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