Essential Thyroid Blood Spot Profile - ZRT Test Kit
The Essential Thyroid Blood Spot Profile can screen for hypothyroidism or hyperthyroidism, monitor dosages for thyroid replacement, and test for autoimmune thyroid disease.
Preparation:
No fasting required. Specimen must be sent to lab by overnight mail Monday-Thursday only. Please read patient instructions very carefully and decide the ideal day for you to begin test.
Test Results:
5-7 Days once the lab receives the specimen. May take longer based on weather, holiday or lab delays.
Thyroid dysfunction can explain a wide variety of symptoms because of the central role of thyroid hormones in directing the metabolic activity of cells. The essential thyroid profile accesses the overall thyroid health, which includes checking for hypothyroidism and hyperthyroidism, determines Free T3 and Free T4 levels, monitors dosages for thyroid replacement and tests for autoimmune thyroid disease.
The Essential Thyroid Blood Spot Profile includes TSH, Free T4, Free T3, and TPOab.
This profile is not only for those requiring a thyroid screening. This profile is also used as a routine screening for:
- Women trying to get pregnant or who are pregnant
- Individuals over the age of 50
- People with other autoimmune disorders, especially those with a history of autoimmune thyroiditis
- Anyone with a family history of thyroid disorders
- People, including children, who have Down’s Syndrome
- People experiencing symptoms of thyroid dysfunction
TSH – Thyroid Stimulating Hormone
Produced by the pituitary, TSH acts on the thyroid gland to stimulate the production of the thyroid hormones T4 and T3. Higher than normal TSH can indicate a disorder of the thyroid gland, while low TSH can indicate over-production of, or excessive supplementation with, T4 and/or T3, which acts in negative feedback on the pituitary to reduce TSH production. Low TSH can also be caused by problems in the pituitary gland itself, which results in insufficient TSH being produced to stimulate the thyroid (secondary hypothyroidism).
Free T4 – Thyroxine
T4 (thyroxine) is the predominant hormone produced by the thyroid gland. It is an inactive hormone and is converted to its active form, T3 within cells. Free T4 is the non-bound fraction of the total T4 circulating in the blood. Free T4 is available to the issues and represents 0.04% of the total T4 levels. High TSH combined with low free T4 levels indicates hypothyroidism while low TSH and high free T4 levels indicate hyperthyroidism.
Free T3 – Triiodothyronine
The active thyroid hormone that regulates the metabolic activity of cells. Free T3 is the non-protein-bound fraction circulating in the blood, representing about 0.4% of the total circulating T3, which is available to tissues. Elevated T3 levels are seen in hyperthyroid patients, but levels can be normal in hypothyroid patients because it does not represent the intracellular conversion of T4 to T3, which comprises about 60% of all T3 formed in tissues.
TPOab – Thyroid Peroxidase Antibodies
Thyroid peroxidase is an enzyme used by the thyroid gland in the manufacture of thyroid hormones by liberating iodine for attachment to tyrosine residues on thyroglobulin. In patients with autoimmune thyroiditis (predominantly Hashimoto’s disease), the body produces antibodies that attack the thyroid gland, and levels of these antibodies in the blood can diagnose this condition and indicate the extent of the disease.
