Thyroxine (T4) Test

Regular price £59.00

Tax included.
Thyroxine (t4) Test (total) is designed to test for Total Thyroxine (T4) hormone and accurately assesses T4 levels in the blood.
  • Test can be used for both men and women. 
  • Test sample can be collected at the comfort of your home.
  • Free delivery in the UK
  • Customers are responsible for shipping their sample to the laboratory.
  • Test kit includes laboratory fee: no additional laboratory cost and tax.
  • Test Result: You will receive your test result via email within 3-5 working days after Laboratory receives your sample. On your test result, you will find your hormone levels in graphics and numbers. You will also find laboratory's comments made by Hormone Specialist PhD Dr In the comment section Doctor will explain your hormone levels and what to do next such as changing your diet, start exercises, using the supplement or start hormone therapy. 
  • Analyse Stability: The dried blood spot samples are stable for more than one month at room temperature. 
  • Test must be used within 12 months after purchase date.

Thyroxine (T4) Test Kit Pack includes 

  • Test Requisition Form includes Symptom Checklist.   
  • Requisition Form to complete including your personal and medical history.   
  • Test kit contains sample collection tools (blood spot card and finger pricks).   
  • Instructions on how to use the blood spot collection kit.
  • Shipping Instruction.
  • Return Envelope.

Thyroxine (T4) is the primary thyroid hormone circulating in the blood. Total T4 includes both free T4 and protein-bound T4, and therefore represents the thyroid gland’s capacity to synthesise, process, and release T4 into the bloodstream. In contrast, free T4 and free T3 are representative of the bioavailability of active thyroid hormones to peripheral tissues. A low level of total T4 with elevated levels of thyroid-stimulating hormone (TSH) and thyroglobulin suggests hypothyroidism caused by either low iodine intake or inhibition of iodine uptake or the iodination of thyroglobulin by goitrogens.

Excessive amounts of iodine can result in either hypo– or hyperthyroidism, depending on preexisting conditions. For example, elderly people who have lived for a long period in a low iodine environment develop autonomous thyroid nodules as a compensatory mechanism to boost thyroid hormone production. When iodine exposure is suddenly increased, these nodules hyper-respond and the result is hyperthyroidism with high T4 production. On the other hand, hypothyroidism as a result of excess iodine can occur when iodine forms iodolipids within the thyroid follicle that inhibit the iodination of thyroglobulin, depressing T4 and T3 synthesis (the Wolff-Chaikoff effect). This can usually be reversed by lowering iodine intake to less excessive amounts, so that thyroid hormone synthesis returns to normal. However, individuals with pre-existing subclinical hypothyroidism or Hashimoto’s disease may progress to a permanent clinical hypothyroid state and require thyroid hormone medication. The reference range for total T4 is 5—10.8 µg/dL. 

      How to Use 

      blood spot use introduction