Thyroid Panel Most Popular

The Thyroid Panel test contains 1 test with 3 biomarkers.

Description: A thyroid panel is a test that is used to evaluate your thyroid function.

Also Known As: Thyroid Test, Thyroid Function Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a Thyroid Panel test ordered?

When symptoms suggest hypo- or hyperthyroidism as a result of a thyroid disorder, a thyroid panel may be conducted.

What does a Thyroid Panel blood test check for?

Thyroid panels are a collection of tests that can be conducted together to assess thyroid gland function and detect thyroid diseases. A thyroid panel includes tests that measure the amount of thyroid hormones in the blood. Hormones are chemical molecules that pass through the bloodstream and regulate or control the body's metabolism, or how it functions and consumes energy.

The following items are usually included on a thyroid panel

  • To test for hyperthyroidism or to monitor treatment, a thyroid panel will include T4 Total.
  • A T3 uptake test is included to determine the free thyroxine index, a tool for measuring thyroid function that corrects for changes in particular proteins that can alter total T4 levels, in addition to the T4 value.

The pituitary gland produces TSH, which is part of the body's feedback mechanism for maintaining constant levels of thyroid hormones T4 and T3 in the blood. The pituitary gland is stimulated to release TSH when thyroid hormone levels fall. TSH then stimulates the thyroid gland's production and release of T4 and T3. Thyroid production turns on and off to keep blood thyroid hormone levels consistent when the system is working properly.

The thyroid gland, a little butterfly-shaped organ that sits flat across the windpipe at the base of the throat, produces two primary hormones: T3 and T4. They work together to help regulate the rate at which the body expends energy. T3 and T4 circulating in the blood are almost entirely bound to protein. The biologically active forms of the hormones are the little sections that are not bound or "free". Tests can determine the quantity of free T3 or free T4 in the blood, as well as the total T3 or total T4.

The total T4 and total T3 tests have been around for a long time, but the quantity of protein in the blood that can bind to the hormone can impact the results. Many people believe that the free T4 and free T3 tests are more accurate reflections of thyroid hormone activity since they are not impacted by protein levels. In the vast majority of cases, the free T4 test has taken the place of the total T4 test. However, some professional standards support the total T3 test, therefore thyroid function can be assessed with either the total T3 or free T3 tests.

Lab tests often ordered with a Thyroid Panel test:

  • TSH
  • Free T4
  • Total T4
  • Free T3
  • Total T3
  • Thyroid Peroxidase and Thyroglobulin Antibodies
  • Calcitonin
  • Thyroglobulin

Conditions where a Thyroid Panel test is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

How does my health care provider use a Thyroid Panel test?

Thyroid panels are used to assess thyroid function and/or aid in the diagnosis of hypothyroidism and hyperthyroidism caused by a variety of thyroid diseases. Typically, the panel will include tests for T3 Uptake and Total Thyroxine.

Thyroid hormones T4 and T3 are generated by the thyroid gland. They aid in the regulation of the body's energy consumption rate and are controlled by a feedback system. The pituitary gland's TSH increases the thyroid's production and release of T4 and T3. The majority of T4 and T3 in the blood is attached to protein. A small percentage of the hormones are free and physiologically active.

The whole amount of hormone or only the free component can be measured in laboratory testing. Many people believe that the free T4 test is a more accurate reflection of thyroid hormone activity, and it has largely supplanted the total T4 test. However, some professional recommendations still advocate the total T3 test, thus a health practitioner can request either free T3 or total T3.

A TSH test is usually the first step in diagnosing thyroid problems. If the TSH level is abnormal, a test for free T4 will usually be ordered. A total T3 or free T3 test is sometimes done as well. This follow-up testing is frequently done automatically by the laboratory. Reflex testing saves the health practitioner time by eliminating the need to wait for the results of the initial test before requesting additional testing to confirm or clarify a diagnosis. The original sample that was submitted when the initial test was requested is usually used for reflex tests.

A thyroid panel may be suggested as an alternative by the health practitioner. This means that all three tests will be done at the same time in order to get a more full picture of thyroid function at the outset.

What do my Thyroid Panel test results mean?

Increased or decreased quantities of thyroid hormones may happen if the thyroid gland's feedback mechanism is not operating properly owing to one of a number of diseases. When TSH levels rise, the thyroid produces and releases insufficient amounts of T4 and T3, resulting in hyperthyroidism symptoms. Hypothyroidism symptoms can occur when thyroid hormone production is reduced.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Free T4 Index (T7)

FTI stands for the Free Thyroxine Index and is also sometimes referred to as T7. It is a calculated value determined from the T3 uptake test and total T4 test and provides an estimate of the level of free T4 in the blood.

T3 Uptake

T3 uptake is also known as T3 Resin Uptake (T3RU) or Thyroid Uptake. It estimates how much thyroid hormone-binding proteins are available in the blood through a calculation based on levels of T3 or T4 added to a person's blood specimen.

T4 (Thyroxine), Total

This test measures the amount of thyroxine, or T4, in the blood. T4 is one of two major hormones produced by the thyroid gland. The total T4 test is used to help diagnose hyperthyroidism and hypothyroidism. It is a useful test but can be affected by the amount of protein available in the blood to bind to the hormone.
*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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