Thyroid Panel Blood Test
Located low on your neck is a butterfly-shaped organ called the thyroid gland. Unless this gland enlarges, you won’t be able to feel it. Your thyroid produces and releases hormones that control your metabolism and several vital body functions, such as body temperature, cholesterol levels, breathing, and heart rate. Thyroid hormone also plays a crucial role in the brain development of infants and children.
What Are The Thyroid Hormones?
Your thyroid gland uses the iodine you consume in your diet to produce two thyroid hormones. These get stored in the thyroid and released when needed. The two thyroid hormones are:
- Triiodothyronine (T3). Your thyroid and other body tissues produce this hormone, which affects vital organs such as your muscles, heart, brain, and digestive system.
- Thyroxine (T4). This is the main thyroid hormone and affects such things as mood, digestion, heart function, and how your body converts food into energy.
What Are Hypothyroidism And Hyperthyroidism?
Measuring the level of thyroid hormones in your blood helps detect an underactive or overactive thyroid, leading to several symptoms and other conditions.
- An underactive thyroid produces insufficient levels of vital thyroid hormones. Although you may have no symptoms in the initial stages, this hormone deficiency can eventually cause memory loss, weight gain, fatigue, dry skin, cold sensitivity, and heart problems.
- An overactive thyroid produces excessive amounts of thyroid hormones and can affect your whole body. Symptoms of hyperthyroidism include unexplained weight loss, anxiety, sweating, irregular heartbeat, tremors, muscle weakness, and brittle hair.
What Is A Thyroid Panel?
A thyroid panel is a blood test that evaluates your thyroid function by checking your levels of:
- Triiodothyronine (T3). This test is also called free triiodothyronine or total triiodothyronine. Most T3 found in your blood is bound to a protein. The unbound or free T3 is the only active form of the hormone. A thyroid panel measures the free and bound T3 levels.
- Thyroxine (T4). This major thyroid hormone depends on a healthy and functioning hypothalamus and pituitary gland to maintain proper blood levels.
- Thyroid-stimulating hormone (TSH). The production and release of T4 by your thyroid occurs after the hypothalamus releases thyrotropin-releasing hormone (TRH). TRH then stimulates your pituitary gland to release TSH, stimulating the thyroid to produce and release T4.
When Should I Get A Thyroid Panel?
Because it serves such a critical role in so many aspects of your health, health care providers often request a thyroid panel. This blood test can help evaluate any treatment you receive for hyperthyroidism and hypothyroidism. A thyroid panel also helps diagnose conditions, such as:
- Thyroid cancer
- Grave’s disease
- Thyroid tumors
- Hashimoto’s disease
What Does A Complete Blood Count Measure?
A complete blood count supplies important information about the number and function of these blood components:
- Red blood cells. These cells carry oxygen from the lungs to other vital organs and the rest of the body. They also transport carbon dioxide from the body to the lungs for exhalation.
- White blood cells. White blood cells help fight bacteria and viruses to prevent infections and diseases.
- Platelets. Platelets are essential cells in blood clotting.
- Hemoglobin. This blood protein contains iron and is vital in transporting oxygen.
What Are Normal Thyroid Panel Levels?
Several factors, such as your health status and age, affect the normal range of thyroid hormones. The American Board of Internal Medicine places the normal reference ranges at these values:
- Thyroid Stimulating Hormone (TSH): 5 to 4 mlU/L
- Thyroxine (T4): Free 0.8-1.8 ng/dL
- Triiodothyronine (T3): Total 80-180 ng/dL
How Do I Prepare For The Test?
Unless you have other blood tests on the day of your thyroid panel, you will not need any special preparation such as fasting. However, you should inform your phlebotomist of any changes in your health or medications you take.
How Is The Test Performed?
We usually draw a blood sample from your arm for a thyroid panel. After placing an elastic band on your upper arm and wiping the withdrawal site with an antiseptic wipe, your phlebotomist collects the sample with a small needle. You may feel a momentary slight sting. The test takes no more than a couple of minutes to complete.
What Else Do I Need To Know?
*This content is for informational purposes only and is not meant to replace consulting with a healthcare professional. Please consult with your primary care physician or healthcare provider before engaging in any services offered by Speedy Sticks.