Thyroid Test TSH fT3 & fT4

About the Thyroid Test TSH fT3 & fT4 

This Thyroid Function Test from GetTested offers a straightforward evaluation of your thyroid function by measuring TSH (Thyroid-Stimulating Hormone), fT3 (Free triiodothyronine), and fT4 (Free Thyroxine).

With the Basic Thyroid Blood Test, monitoring your thyroid health has never been easier. You can collect a small blood sample from the comfort of your home using our user-friendly test kit. Once collected, send the sample to our ISO-15189 certified laboratory in the UK using the enclosed return packaging provided.

Thyroid Functions assessed by the Thyroid Test 

GetTested's Thyroid Test TSH, fT3 & fT4 measures free T3, free T4, and TSH levels, to assess Thyroid function. 

fT3 (Free Triiodothyronine)
fT3 is a crucial thyroid hormone that regulates the body's metabolism, heart rate, and body temperature. Directly assessing fT3 levels can offer insights into the functional status of the thyroid. 

fT4 (Free Thyroxine)

fT4 circulates freely in the bloodstream and it is the main hormone the thyroid gland produces. It exists in two forms: bound to proteins or free (unbound). FT4 represents the portion of thyroid hormone that is not bound to proteins and is available to perform its biological functions. Measuring the fT4 levels helps assess the thyroid's ability to produce and regulate thyroid hormones properly.

TSH (Thyroid-Stimulating Hormone)

TSH is a hormone that plays a crucial role in regulating the thyroid gland's activity. When the thyroid hormone levels in the blood are low, the pituitary gland releases more TSH. This is to stimulate the thyroid to produce and release more thyroid hormones. Conversely, when thyroid hormone levels are high, the pituitary gland reduces TSH production to decrease thyroid hormone production. Monitoring TSH levels helps assess the overall function of the thyroid gland and it is often the first test doctors perform when they suspect thyroid issues. 

Additional testing

If you wish to evaluate thyroid antibodies, we offer another thyroid test, Thyroid Test TPO, which assesses three different types of antibodies. The presence of thyroid antibodies indicates an autoimmune thyroid disorder, specifically Hashimoto's disease. It's possible to have normal TSH, T3, and T4 levels while still having thyroid antibodies. 

Understanding the Thyroid Feedback Loop

The thyroid gland is a crucial component of the hypothalamic-pituitary-thyroid axis, and it operates through a negative feedback loop. Thyroid-Releasing Hormone (TRH) from the hypothalamus stimulates the release of Thyroid Stimulating Hormone (TSH) from the pituitary gland. TSH regulates the production of thyroid hormones, including T4 (the inactive form) and T3 (the active form that cells use). Approximately one-third of T4 is converted into active T3, provided the individual has a healthy liver, balanced gut flora, and adequate nutritional levels (especially selenium and zinc – for nutritional assessments, consider our Nutrition Test). Factors like heavy metals, environmental toxins, alcohol, smoking, inflammation, insulin resistance, and certain medications can inhibit the conversion of thyroid hormones. 

The importance of the Thyroid Test TSH fT3 & fT4:Thyroid disorders

Thyroid disorders are more common among women than men, and hypothyroidism affects 15-20% of women over the age of 50. When the thyroid fails to produce or release enough thyroid hormones, it can slow down metabolism. An underactive thyroid can lead to weight gain, depression, fatigue, and heightened sensitivity to cold temperatures. 

Symptoms of Hypothyroidism (Underactive Thyroid)

• Fatigue
• Weight gain
• Cold sensitivity
• Depression
• Constipation
• Dry skin
• Brittle hair and nails
• Brain fog
• Forgetfulness

Symptoms of Hyperthyroidism (Overactive Thyroid)

• Fatigue
• Mood swings, anxiety, and irritability
• Heat sensitivity
• Heart palpitations
• Difficulty sleeping
• Swelling in the neck due to an enlarged thyroid gland (goitre)
• Attention difficulties

Please note that the intake of thyroid medication or supplementation with tyrosine or phenylalanine can influence thyroid test results. 

How GetTested's Thyroid Test TSH fT3 & fT4 works

This thyroid test involves a blood sample collected at home through a finger prick. You'll then apply the blood to a special paper with circles designed for blood drops. The sample is sent to the lab for analysis. As soon as the laboratory completes the analysis of your sample, your results will be delivered digitally to you in a secure manner. The cost includes shipping the sample to the lab. Rest assured that your personal information and test results are handled with the utmost confidentiality and privacy.