THYROID Panel (TSH + Free T3 + Free T4)

Thyroid Panel (TSH + Free T3 + Free T4): Complete Guide

Thyroid hormones regulate our body's metabolism and influence virtually every organ system in the body. They tell organs how fast or slow they should work. Thyroid hormones also regulate the levels of thyroid hormone consumption of oxygen and production of heat. Thyroid problems, such as an overactive thyroid (hyperthyroidism) or underactive thyroid, can severely affect metabolism. This panel includes comprehensive testing of the thyroid stimulating hormone (TSH) in addition to free thyroxine (T4) and free triiodothyronine (T3). When the thyroid gland does not produce enough hormone, the body uses energy at a slower pace than it should. This condition, underactive thyroid, is called hypothyroidism. Panel includes:

• TSH
• Free T3
• Free T4

 You can add reverse T3 and thyroid AB and anti-TPO antibodies by adding those tests to your cart.

Lab Test Collection Instructions

Dietary supplements containing biotin may interfere in assays and may skew results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.

The Importance of Thyroid Tests: All You Need to Know

Being a part of the endocrine system, the thyroid gland is an organ similar in terms of shape to a butterfly, at the base of your neck. Usually, its length lies between 2 and 5 inches, while its weight does not exceed 30 grams for an adult. It is critical to ensure that sensitive information regarding thyroid health is shared only with qualified professionals.

The thyroid is often overlooked when considering your health, but luckily, the thyroid test cost is smaller and smaller every year. The thyroid influences the way every cell, tissue, muscle, or bone interacts and controls the way our metabolism can transform nutritious substances into energy.

Thyroid cancer and Hashimoto’s disease are just two examples of the disorders in the hormone-producing process that cause thyroid problems, indicating the presence of an autoimmune disorder. Healthcare providers recommend a blood test once a year to check your health properly, as any neglected disorder like Hashimoto’s disease can cause severe health issues.

Why Thyroid is So Important?

The thyroid gland is one of the most important parts of your body located in the front of your neck; it releases hormones that are responsible for protein production and control of metabolism. It regulates vital body functions such as breathing, body weight, body temperature, levels of cholesterol, heart rate, menstrual cycles for women, digestion, growth, the brain, and the body’s most important functions like bones.

We can think of the thyroid gland as an oven and the pituitary gland as its thermostat. Whenever the “oven” becomes colder, the “thermostat” gets notified and starts producing TSH to stimulate the thyroid hormones, which leads to warming. When the opposite occurs, the pituitary gland slows down the TSH production and cools you off.

The thyroid gland releases two hormones: T3 (Triiodothyronine) and T4 (Thyroxine). These are produced using iodine found in foods: sea salt, seafood, bread, milk, etc. A radioactive iodine uptake test, also known as a thyroid uptake test or thyroid scan, can help determine how effectively the thyroid uses iodine. T3 and T4 are regulating heart rates, helping the digestive system to process food at a higher rate.

Hence, if T3 and T4 are low, you may have a slower heart rate than usual and also gain weight as an effect of constipation. Meanwhile, if T3 and T4 are high, you may face the opposite, facing a faster heart rate and diarrhea, which will lead to weight loss. 

Types of Thyroid Tests

A healthcare professional can identify hormonal imbalances by using a variety of thyroid function tests. You can go for individual tests or more complex test panels that use a blood sample. Let’s take a closer look at a few of them. Remember that the thyroid test cost is getting lower, so now is the right time to test your thyroid.

The Comprehensive Thyroid Panel

The comprehensive thyroid panel is the most elaborate and cost-efficient hormonal check for the thyroid. It reveals all possible disorders that oftentimes go undetected with a more limited assessment.

This test panel can explore all possibilities of thyroid disorders, including hypothyroidism/Hashimoto's disease. It comprises TSH, Free T3, Free T4, Reverse T3, Thyroglobulin Antibody, and Thyroid Peroxidase Antibody (Anti-Tpo). 

TSH: Thyroid Stimulating Hormone

The TSH test, or thyroid-stimulating hormone test, is the best and most common test to check the possibility of thyroid disease in the context of nonexistent dysfunction of the pituitary gland. If this TSH test results in normal values of 0.450−4.500 μIU/mL (>10 yr old), it means that the TSH levels are in the normal range and that there is enough thyroid hormone production, not too much thyroid hormone.

An increased level of TSH may suggest that the pituitary gland sends a message that the deficit thyroid does not produce enough hormones, which leads to hypothyroidism.

By comparison, if the TSH level is very low, it means that a higher number of hormones was produced and you may suffer from hyperthyroidism. 

Free T3 ( Free Triiodothyronine Test)

The test for this hormone is usually useful to determine whether a patient suffers from hyperthyroidism or not. Normal levels for T3 lie between 100 and 200 ng/Dl.

Whenever you are facing symptoms such as constipation, anxiety, depression, dry skin, increased heart rate, or sleeping disorders, a test may be required.

Free T4 (Free Thyroxine Test)

The thyroid gland secretes and produces T4, which is well known as thyroxine. The thyroxine binds with the proteins and arrives in your tissues throughout the bloodstream.

Further on, the T4 and the proteins split and T4 becomes free to convert itself in T3, a more active form. In general, doctors recommend testing both TSH and free T4 to get to a clearer picture in case of hypothyroidism. The reference interval for this indicator is 0.82-1.77 ng/dl (>19 years old).

Symptoms of Thyroid Dysfunction

Many disorders may be associated with thyroid and may appear at any age as a result of various situations, such as injuries, deficiencies in our diet, or disease.

The most common disorders associated with thyroid are hypothyroidism and hyperthyroidism, which are explained below:

Hypothyroidism

It is characterized by the insufficient production of thyroid hormones. The most common cause of hypothyroidism consists in the iodine deficit. The second most frequent cause for hypothyroidism is a particular inflammatory disorder called Hashimoto's thyroiditis, which is associated with elevated thyroid antibodies, while the most common cause of hyperthyroidism is Graves' disease.

In both cases, the patient will develop goiter. Hashimoto's thyroiditis cause is not yet determined, involving genetic and environmental factors.

The symptoms associated with the deficit of thyroid hormones include dry skin, voice changing, excessive tiredness, weight gain, sleeping issues, muscular cramps, cardiac insufficiency, menstrual disorders, and liquid across the heart and throughout the abdominal cavity.

Without proper treatment, hypothyroidism leads to cardiac and respiratory insufficiency, fatigue, weight gain, low mood, and more health consequences that impair quality and quantity of life.

Hyperthyroidism

By comparison, hyperthyroidism is characterized by an excess of thyroid hormones. This disorder makes the heart work more, which determines a series of secondary disorders; the most frequent ones are sinus tachycardia (abnormal cardiac rhythm, > 100 beats/minute) as well as irregular heartbeat and cardiac arrhythmia.

An associated symptom with this disorder consists of palpitations. An excess of thyroid hormones determines the heart to pump blood faster; therefore, the cardiac muscle will require more oxygen.

Order Your Thyroid Panel Today

Find out more about your thyroid by choosing the right thyroid test today and receive your test results conveniently, which will include reference ranges. Go to DiscountedLabs.com and get a variety of thyroid lab test options, including Cleveland Clinic recommended test combinations and American Thyroid Association endorsed accessible locations in more than 30 states in the US.

Frequently Asked Questions

What is included in a full panel testing of thyroid?

A full thyroid panel includes tests for thyroid-stimulating hormone (TSH), free triiodothyronine (T3), and free thyroxine (T4). These tests help evaluate thyroid function by measuring hormone levels in the blood, aiding in diagnosing thyroid disorders like hypothyroidism or hyperthyroidism.

Are there any specific preparations required before taking a thyroid panel test?

Before taking a thyroid panel test, there are some specific preparations that may be required. Here are some general guidelines to help you prepare for a thyroid panel test:

1. Follow any fasting instructions: Depending on the specific tests included in the thyroid panel, your healthcare provider may recommend fasting before the test. This usually involves not eating or drinking anything except water for a certain period of time before the test.

2. Inform your healthcare provider about medications: Make sure to inform your healthcare provider about any medications, supplements, or herbal remedies you are taking, as these can affect the results of the thyroid panel test.

3. Timing of the test: Some healthcare providers recommend taking the thyroid panel test in the morning when thyroid hormone levels tend to be most stable. Follow any specific timing instructions provided by your healthcare provider.

4. Wear loose-fitting clothing: If blood will be drawn for the test, wearing loose-fitting clothing can make it easier for the healthcare provider to access your arm.

5. Stay relaxed: Try to stay relaxed before and during the test to help ensure an accurate reading of your thyroid function.

It is important to follow any specific instructions provided by your healthcare provider when preparing for a thyroid panel test to ensure accurate results.

How do you interpret the results of a thyroid panel?

Interpreting the results of a thyroid panel involves looking at various markers such as TSH (Thyroid-Stimulating Hormone), T3 (Triiodothyronine), and T4 (Thyroxine). Here are some general guidelines for interpreting the results:

- TSH levels: High TSH levels may indicate an underactive thyroid (hypothyroidism), while low TSH levels may suggest an overactive thyroid (hyperthyroidism).

- T3 and T4 levels: Abnormal levels of these hormones can also indicate thyroid dysfunction. High T3 and T4 levels may suggest hyperthyroidism, while low levels may indicate hypothyroidism.

- Thyroid antibodies: The presence of certain antibodies, such as anti-TPO antibodies, can indicate autoimmune thyroid disease, such as Hashimoto's thyroiditis or Graves' disease.

The combination of these tests provides a comprehensive picture of thyroid function:

• Primary Hypothyroidism: High TSH with low Free T4 and/or Free T3
• Primary Hyperthyroidism: Low TSH with high Free T4 and/or Free T3
• Subclinical Hypothyroidism: High TSH with normal Free T4 and Free T3
• Subclinical Hyperthyroidism: Low TSH with normal Free T4 and Free T3

It's important to keep in mind that a variety of factors, such as medications, pregnancy, and specific medical conditions, can affect thyroid function. Therefore, a healthcare professional should always interpret the results in light of the patient's overall health and symptoms.

It is important to consult with a healthcare provider or endocrinologist for a comprehensive interpretation of your thyroid panel results, as they can provide personalized insights based on your individual health history and symptoms.

How can high-dose biotin supplements interfere with thyroid test results?

High-dose biotin supplements, often taken for hair loss, can potentially impact thyroid test results. Biotin, also known as vitamin B7, is a water-soluble vitamin that is commonly found in hair and nail supplements. When individuals consume high doses of biotin, it can lead to falsely elevated or decreased thyroid hormone levels in blood tests.

Thyroid function tests are commonly used to diagnose and monitor thyroid disorders such as hypothyroidism and hyperthyroidism. However, biotin interference in these tests can result in inaccurate readings. This happens because some lab tests use biotin technology, in which biotin binds to streptavidin to measure certain hormones, such as triiodothyronine (T3), thyroid-stimulating hormone (TSH), and thyroxine (T4).

When high levels of biotin are present in the blood due to supplementation, it can interfere with these assays by causing false results. For example, elevated biotin levels may lead to artificially low TSH levels, making it appear as though the individual has hyperthyroidism when they do not.

It is essential for individuals taking high-dose biotin supplements to inform their healthcare providers about their usage before undergoing any thyroid function tests. Healthcare professionals may recommend temporarily discontinuing biotin supplements several days before testing to ensure accurate results. Additionally, in some circumstances it might be necessary to use alternative testing techniques that are not biotin interference-affected.

References

Overview of Thyroid Tests: InformedHealth Guide – NCBI

Thyroid Function Tests: An Overview – American Thyroid Association

Thyroid Blood Tests: Types, Procedures, and Preparation – Cleveland Clinic

Thyroid Function Tests: Common Assessments and Interpretation – Mount Sinai

Understanding Thyroid Function Tests – Healthline