Thyroid, T4, FT4, T3 Up, TSH, FT3, T3 Total, T3R

The Thyroid, T4, FT4, T3 Up, TSH, FT3, T3 Total, T3R panel contains 7 tests with 9 biomarkers.

Brief Description: The Thyroid, T4, FT4, T3 Up, TSH, FT3, T3 Total, T3R Panel is a detailed assessment of thyroid function, providing a comprehensive overview of the thyroid hormone production, metabolism, and regulatory mechanisms. This panel includes measurements of both bound and unbound forms of thyroxine (T4) and triiodothyronine (T3), the thyroid-stimulating hormone (TSH), and the reverse T3 (T3R), offering insights into various aspects of thyroid health. This in-depth analysis is crucial for diagnosing thyroid disorders, guiding treatment decisions, and monitoring the effectiveness of interventions.

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: Specifc to TSH: Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks.

According to the assay manufacturer Siemens: "Samples containing fluorescein can produce falsely depressed values when tested with the Advia Centaur TSH3 Ultra assay."

When and Why the Panel May Be Ordered

This panel is typically ordered for individuals presenting symptoms suggestive of thyroid dysfunction, such as unexpected weight changes, mood fluctuations, changes in energy levels, or irregularities in heart rate. It's also crucial for monitoring patients with known thyroid disorders, assessing the efficacy of ongoing treatment, and adjusting therapeutic approaches based on comprehensive hormonal feedback.

What the Panel Checks For

T3 Reverse (T3R)

Measures the level of reverse T3, an inactive form of T3 that can increase in conditions of thyroid dysfunction and in non-thyroidal illness.

T3 Total

Assesses the total amount of triiodothyronine, including both the free and bound forms, providing a general overview of T3 availability.

T3 Uptake (T3 Up)

Evaluates the binding capacity of proteins that carry thyroid hormones in the blood, offering indirect information about thyroid function and hormone availability.

T3 Free (FT3)

Measures the unbound, active form of T3, giving insight into the metabolic activity driven by thyroid hormones.

T4 Total

Determines the total concentration of thyroxine, including both bound and free forms, to assess overall thyroid hormone production.

T4 Free (FT4)

Measures the unbound, active form of T4, which is a precursor for T3 and crucial for understanding thyroid health.

TSH

Evaluates the level of thyroid-stimulating hormone, which is produced by the pituitary gland and regulates thyroid hormone production.

Conditions or Diseases Detected by the Panel

Hypothyroidism

Characterized by reduced thyroid hormone production, leading to a slowdown in metabolic processes. High TSH and low FT4/FT3 levels typically indicate this condition.

Hyperthyroidism

Marked by excessive thyroid hormone production, accelerating metabolism. Low TSH and high FT4/FT3 levels usually suggest hyperthyroidism.

Thyroiditis

Refers to inflammation of the thyroid, which can cause transient hyperthyroidism followed by hypothyroidism. The panel tracks the progression of thyroid hormone levels through these phases.

Non-thyroidal Illness Syndrome

Characterized by abnormal findings on thyroid function tests due to a non-thyroidal illness, with elevated T3R as a key marker.

Using the Results in Treatment and Monitoring

Hypothyroidism

Treatment typically involves thyroid hormone replacement therapy. Regular monitoring of TSH and FT4 levels helps adjust medication dosage to ensure optimal thyroid function.

Hyperthyroidism

Treatment options include antithyroid medications, radioactive iodine, or surgery. Monitoring TSH, FT4, and FT3 levels guides the treatment's effectiveness and dosage adjustments.

Thyroiditis

Management may vary depending on the condition's phase. The comprehensive nature of the panel allows for close monitoring of thyroid function changes, guiding treatment accordingly.

Non-thyroidal Illness Syndrome

Treatment focuses on the underlying illness. T3R levels, along with other markers, help distinguish this condition from primary thyroid disorders, guiding appropriate management strategies.

The Thyroid, T4, FT4, T3 Up, TSH, FT3, T3 Total, T3R Panel provides an essential tool for diagnosing and managing thyroid disorders, offering a detailed picture of thyroid hormone production, regulation, and action. By evaluating the intricate balance of thyroid hormones and their regulators, healthcare professionals can develop targeted treatment strategies, monitor disease progression, and adjust therapies as needed to manage conditions effectively and improve patient outcomes.

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.

Also known as: Reverse T3, Reverse Triiodothyronine, RT3, T3 Reverse RT3 LCMSMS, Triiodothyronine Reverse

T3 Reverse, LC/MS/MS

Reverse T3 produced in the thyroid comes from the conversion of the storage hormone T4. Your body, especially the liver, can constantly be converting T4 to RT3 as a way to get rid of any unneeded T4. In any given day approx. 40% of T4 goes to T3 and 20% of T4 goes to Reverse T3. However in any situation where your body needs to conserve energy and focus on something else, it will change the above percentages, changing the conversion of RT3 to 50% or more, and the T3 goes down, down. Examples are emotional, physical, or biological stress, such as being chronically or acutely sick (the flu, pneumonia, etc), after surgery, after a car accident or any acute injury, chronic stress causing high cortisol, being exposed to an extremely cold environment, diabetes, aging, or even being on drugs like beta blockers and amiodarone.

Also known as: Triiodothyronine

T3, Total

Triiodothyronine (T3) is a thyroid hormone. It plays an important role in the body's control of metabolism.

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.

Also known as: Free T3, FT3, T3 Free

T3, Free

This test measures the amount of triiodothyronine, or T3, in the blood.

Also known as: T4 Thyroxine Total

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.

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.

Also known as: Free T4, FT4, T4 Free

T4, Free

The free T4 test is not affected by protein levels. Since free T4 is the active form of thyroxine, the free T4 test is may be a more accurate reflection of thyroid hormone function.

Also known as: Thyroid Stimulating Hormone, Thyroid Stimulating Hormone (TSH), Thyrotropin

TSH

A TSH test is a lab test that measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland. It tells the thyroid gland to make and release thyroid hormones into the blood.

TSH

*Important Information on Lab Test Processing Times: Ulta Lab Tests is committed to informing you about the processing times for your lab tests processed through Quest Diagnostics. Please note that the estimated processing time for each test, indicated in business days, is based on data from the past 30 days across the 13 Quest Diagnostics laboratories for each test. These estimates are intended to serve as a guide and are not guarantees. Factors such as laboratory workload, weather conditions, holidays, and the need for additional testing or maintenance can influence actual processing times. We aim to offer estimates to help you plan accordingly. Please understand that these times may vary, and processing times are not guaranteed. Thank you for choosing Ulta Lab Tests for your laboratory needs.

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