TSH, Free T4, Free T3, and TPO

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: Free T3, FT3, T3 Free

T3, Free

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

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: Anti-Thyroid Microsomal Antibody, Anti-TPO, Thyroid Peroxidase Antibodies TPO, TPO

Thyroid Peroxidase

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


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.


*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.

The TSH, Free T4, Free T3, and TPO panel contains 4 tests with 5 biomarkers.

Brief Description: The TSH, Free T4, Free T3, and TPO Panel is a specialized diagnostic tool designed to evaluate thyroid function and autoimmunity. By measuring key thyroid hormones and antibodies, this panel provides crucial insights into thyroid health, aiding in the diagnosis and management of thyroid disorders.

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 Is This Panel Ordered?

Healthcare providers may order this panel for individuals exhibiting symptoms of thyroid dysfunction, such as unexplained weight changes, mood swings, energy level fluctuations, or irregularities in heart rate and body temperature. It's also valuable for monitoring the effectiveness of thyroid treatments and assessing the presence of autoimmune thyroid conditions.

In-Depth Test Analysis

  • Thyroid Stimulating Hormone (TSH): TSH is a pituitary hormone that regulates thyroid activity. Abnormal levels can indicate hypothyroidism or hyperthyroidism.
  • T3 Free (FT3): FT3 measures the unbound, active form of triiodothyronine. It's crucial for understanding how much active thyroid hormone is available for the body's use.
  • T4 Free (FT4): FT4 assesses the unbound form of thyroxine, providing insights into the thyroid's functional status.
  • Thyroid Peroxidase Antibodies (TPO): TPO antibodies can indicate autoimmune thyroid diseases, such as Hashimoto's thyroiditis or Graves' disease, where the immune system mistakenly targets the thyroid.

Detectable Conditions and Diseases

This panel is instrumental in identifying and managing several thyroid-related conditions:

  • Hypothyroidism: Characterized by insufficient thyroid hormone production, often signaled by elevated TSH and low FT4 levels.
  • Hyperthyroidism: Marked by excessive thyroid hormone production, typically reflected in suppressed TSH and elevated FT3 or FT4 levels.
  • Hashimoto's Thyroiditis: An autoimmune disorder where TPO antibodies attack the thyroid, gradually leading to hypothyroidism.
  • Graves' Disease: Another autoimmune condition, but one that causes hyperthyroidism, potentially indicated by TPO antibodies and abnormal hormone levels.

Clinical Application of Results

Healthcare professionals use this panel's results to tailor treatment strategies for thyroid disorders. For hypothyroidism, they may prescribe synthetic thyroxine, adjusting the dose based on FT4 and TSH levels. In hyperthyroid cases, treatment could involve antithyroid medications, radioactive iodine, or surgery, with ongoing monitoring of thyroid hormone levels. The presence of TPO antibodies might influence the choice of treatment and monitoring frequency due to the autoimmune aspect of the patient's thyroid condition.

The TSH, Free T4, Free T3, and TPO Panel is a cornerstone in the diagnosis and management of thyroid health, providing a comprehensive snapshot of thyroid function and autoimmunity. Its detailed insights enable personalized treatment plans, ensuring patients receive the most effective care for their specific thyroid condition, thereby optimizing their overall health and well-being.

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

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