


Free T4, also known as thyroxine, is a hormone produced by the thyroid gland. It plays a crucial role in our metabolism and energy balance.
Measuring Free T4 is useful for assessing thyroid function. It is especially relevant when experiencing symptoms of an overactive or underactive thyroid, such as unexplained weight change, fatigue, or mood swings.
Free T4 levels help in evaluating thyroid function. It provides insight into how well the thyroid gland produces and secretes hormones.
A high level of Free T4 may indicate hyperthyroidism, a condition in which the thyroid gland produces too much hormone. This can lead to symptoms such as weight loss, nervousness, and a rapid heartbeat.
A low level of Free T4 may indicate hypothyroidism, where the thyroid gland does not produce enough hormone. This can lead to symptoms such as weight gain, fatigue, and cold intolerance.
Free T3, or triiodothyronine, is another important hormone produced by the thyroid gland. It is even more active than T4 and has a strong influence on metabolism.
Testing for Free T3 is useful for a more in-depth evaluation of thyroid function, especially if symptoms or results from other thyroid function tests are contradictory or unclear.
Free T3 levels provide an accurate picture of thyroid activity and are particularly useful in diagnosing hyperthyroidism or in cases where T4 levels are normal but symptoms of a thyroid disorder persist.
High levels of Free T3 may indicate hyperthyroidism, which can result in symptoms such as increased heart rate, anxiety, and sleep problems.
Low levels of Free T3 may indicate hypothyroidism, with possible symptoms such as fatigue, depression, and a sluggish metabolism.
Answers to what people usually want to know.
After ordering we generate a referral letter and email you the instructions. You pick a collection point yourself and book an appointment there. Blood is drawn at the location, processed at the lab, and your result arrives digitally.
Usually very quickly. Collection points typically have slots within a few days, sometimes even same-day. It depends on how busy the location is. For a few specialist analyses we first ship collection materials, which takes a bit longer.
At most collection points yes. Some accept walk-ins. This is clearly indicated per location. You choose the location that works best for you.
Free T4 and FT3; for thyroid function.



€35.95EUR
That depends on the test. Whether fasting is required, and from what time, is clearly stated in the instructions you receive after ordering. No surprises at the counter.
It varies per analysis: from same-day to a few working days. Standard values often come back quickly; analyses that go to an external lab can take a bit longer. You get an email with a link to your digital result, including a short explanation per value.
We work with 1,000+ collection points across the Netherlands. After ordering you'll see which locations near you are available and you pick where you'd like to go.
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