Free T3 – what do your numbers mean?
Have you had your Free T3 level measured and are unsure what the numbers mean? Here you'll find a clear explanation of the normal range, what a too high or too low level can mean, and when it makes sense to get tested.
What is the normal range for Free T3?
What is the normal range for Free T3?
The normal range for Free T3 in adults over 20 years is between 3.9 and 6.8 pmol/L. In children and adolescents, the values vary depending on age, for example, from 2.7–10.0 pmol/L for newborns to 3.9–7.7 pmol/L for adolescents between 11 and 20 years. Pregnancy can also affect the levels, with values typically being lower, for example, 3.8–6.0 pmol/L in the first trimester. These variations are due to hormonal changes and differences in metabolism. Being close to the reference values can indicate initial thyroid problems, and it is important to consult a doctor for further assessment.
What does a low level mean?
A low level of Free T3 can indicate hypothyroidism, where the thyroid gland produces too little hormone. Symptoms may include fatigue, weight gain, cold intolerance, dry skin, and hair loss. Causes can include autoimmune diseases such as Hashimoto's thyroiditis, iodine deficiency, or side effects from medication. Particularly vulnerable groups include the elderly, people with a family history of thyroid disease, and women after pregnancy. If you experience symptoms of an underactive thyroid, you should contact a doctor for a blood test and potential treatment, which often involves thyroid hormone supplementation.
What does a high level mean?
A high level of Free T3 can be a sign of hyperthyroidism, where the thyroid gland produces too much hormone. Symptoms include nervousness, weight loss, palpitations, sweating, and heat intolerance. Common causes are Graves' disease, nodular goiter, or overdose of thyroid hormone. If you experience these symptoms, it is important to seek medical attention quickly, as untreated hyperthyroidism can lead to serious complications such as heart problems. Treatment may include medication, radioactive iodine, or surgery depending on the cause and severity of symptoms.
Get your Free T3 level tested
At Celto, you can order a blood test for Free T3 directly online – without a referral from your doctor and without long waiting times. We have over 34 sample collection sites at public hospitals throughout Denmark, and your samples are analyzed in the same accredited laboratories used by the rest of the healthcare system. You will receive your results directly on sundhed.dk, just like all other blood tests from the public system.
How it works
When you order a blood test from Celto, you choose which markers you want tested – no doctor's referral needed. After your purchase, you will receive an email with a link to our booking system, where you choose a time and place. The blood sample itself is taken by authorized healthcare personnel and typically only takes a few minutes.
Where you can get tested
Celto has over 34 sample collection sites at public hospitals and clinics throughout Denmark. You choose the location that suits you best among our partners, and there are typically available appointments within a few days. Find your nearest sample collection site →
How to get your results
Your blood samples are analyzed in the same laboratories used by your own doctor and the rest of the healthcare system, with the exact same quality and the same tests. You will receive your results directly on sundhed.dk within a few business days, and Celto will also send an easy-to-understand review of your values so you know what the numbers mean.