Thyroid Profile, Free
The free thyroid profile measures TSH, Free T3, and Free T4: the active thyroid hormones. This panel provides a comprehensive assessment of thyroid function and is preferred over total hormone levels.
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- Includes Doctor Consultation
- Physician-reviewed
- Same Day Collection
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What the Thyroid Profile, Free test tells you
This panel reports three results from one blood sample: thyroid stimulating hormone (TSH), free thyroxine (FT4) and free tri-iodothyronine (FT3). Together they describe both ends of a feedback loop. The pituitary gland releases TSH to tell the thyroid how much hormone to make; the thyroid responds by releasing T4 and, in smaller amounts, T3; and the rising hormone levels then tell the pituitary to ease off. Because the pituitary is exquisitely sensitive, TSH usually moves in the opposite direction to the thyroid hormones, and often moves first.
The word free is what distinguishes this panel from the total profile. Almost all thyroid hormone in the blood is bound to carrier proteins and is not available to tissues; only the small unbound fraction can enter cells and act, and that is the fraction measured here. Measuring the free hormones removes a common source of confusion, because pregnancy, oestrogen-containing contraceptives, hormone therapy, and some liver and kidney conditions change how much carrier protein is present without changing thyroid function at all. In those situations a total measurement can look abnormal while the free measurement remains entirely representative, which is precisely why the free panel is usually preferred.
What your doctor reads is the pattern rather than any single value. A raised TSH with low free hormones points towards an underactive gland, a suppressed TSH with high free hormones towards an overactive one, and mixed or unexpected combinations raise other possibilities: a pituitary problem, interference in the assay, a recent medication change, or the temporary shifts that accompany serious illness. Antibody testing is often added when the pattern suggests an autoimmune cause.
Comprehensive thyroid function assessment, evaluation of thyroid symptoms (fatigue, weight changes, palpitations), and monitoring thyroid medication dosing.
- Assess function in one draw
TSH with both free hormones gives your doctor the pituitary signal and the gland's response from a single sample.
- Unaffected by binding proteins
Free measurements stay representative during pregnancy, on oestrogen-containing contraception and in liver disease.
- Explain common symptoms
Fatigue, weight change, palpitations, hair loss and cold or heat intolerance are all reasons to look at thyroid function.
- Guide medication dosing
The pattern across the three results is what your doctor uses to decide whether a thyroid dose needs adjusting.
Reasons your doctor may request the Thyroid Profile, Free test
Your doctor may order this test for any of the reasons below. Some are routine checks, others follow specific symptoms or an earlier result.
Symptoms of an under- or overactive thyroid
- Symptoms suggesting an underactive thyroid, such as fatigue, weight gain, cold intolerance or constipation.
- Symptoms suggesting an overactive thyroid, such as palpitations, tremor, heat intolerance, anxiety or weight loss.
An abnormal TSH
- An abnormal screening TSH that needs the free hormones to interpret it.
Treatment, pregnancy & thyroid findings
- Monitoring of levothyroxine or antithyroid treatment.
- Thyroid assessment in pregnancy or before conception, where carrier proteins change but free hormones stay representative.
- A goitre, a thyroid nodule, or a family history of thyroid disease.
This is reported as a Multi-parameter panel, so your report gives TSH, free T4 and free T3 separately and they are read as a pattern. TSH tends to shift before the hormones do, and in the opposite direction. A high TSH alongside low free hormones suggests the gland is underactive; a suppressed TSH with high free hormones suggests the reverse. Unexpected combinations raise other possibilities: a pituitary problem, assay interference, a recent dose change, or the shifts that follow serious illness. The free fractions are not disturbed by pregnancy, oestrogen-containing medicines or the liver and kidney conditions that shift carrier proteins, which is why this panel is preferred. Biotin supplements can distort the results, and TSH lags behind change, so mention recent illness, supplements and any dose adjustment. Your doctor reads the combination with your symptoms.
Medically reviewed by Dr Nirupama Sabhapathy
This test is reported descriptively rather than on a numeric scale: each finding below explains what your report may say.
This panel reports TSH, free T3 and free T4 together to assess thyroid function. See your detailed report for individual values.
Ranges are a guide: your physician interprets your result alongside your symptoms and history.
What a higher result can point to
- Graves' disease, the commonest cause of an overactive thyroid.
- A toxic nodule or multinodular goitre producing hormone independently of TSH.
- Thyroiditis, where stored hormone leaks from an inflamed gland.
- Excessive or over-replaced thyroid hormone medication.
- Excess iodine intake, including from contrast dye or certain supplements.
- A pituitary problem producing the unusual combination of a raised TSH with raised free hormones.
What a lower result can point to
- Hashimoto's thyroiditis and other autoimmune damage to the gland.
- Insufficient thyroid hormone replacement, or doses taken irregularly.
- Thyroid surgery, radioactive iodine treatment or radiotherapy to the neck.
- Pituitary disease, where a low or inappropriately normal TSH accompanies low free hormones rather than the usual raised TSH.
- Severe non-thyroidal illness, which temporarily lowers free T3 in particular.
- Medicines including amiodarone, lithium and some cancer immunotherapies.
These are possibilities, not diagnoses. A single value outside the reference range is interpreted alongside your symptoms, history and other tests: your doctor decides what it means for you.
What this test cannot tell you
- The pattern can be misleading during and shortly after severe illness, when hormone levels shift without thyroid disease.
- High-dose biotin supplements interfere with several thyroid assays and can produce a convincingly abnormal set of results.
- TSH lags behind change, so results drawn soon after a dose adjustment may not yet reflect the new state.
- Free hormone results are method-dependent, so serial comparisons are most reliable within one laboratory.
Risks of the blood draw
- Mild bruising or brief soreness where the needle went in.
- Occasional lightheadedness, which settles after a few minutes of rest.
- Bleeding or infection at the site, which is rare with sterile single-use equipment.
- 1The panel reports the pituitary signal (TSH) alongside the two biologically active thyroid hormones.
- 2TSH usually moves in the opposite direction to the free hormones.
- 3Free fractions are unaffected by changes in carrier proteins, unlike total measurements.
- 4The combination of results, not one value, is what identifies the problem.
- 5Recent illness, biotin supplements and dose changes all need to be mentioned for correct interpretation.
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Frequently Asked Questions
Everything you need to know about the Thyroid Profile, Free test. Can't find what you're looking for?
Talk to our team→An underactive thyroid tends to cause tiredness, weight gain, feeling cold, constipation and dry skin. An overactive thyroid tends to cause palpitations, weight loss, feeling hot, tremor and anxiety. Symptoms overlap with many other conditions, which is why the free thyroid profile measures TSH, free T4 and free T3 together rather than relying on how you feel.
A suppressed TSH with high free hormones suggests an overactive thyroid. The commonest cause is Graves' disease; others are a toxic nodule or multinodular goitre, thyroiditis where stored hormone leaks from an inflamed gland, too high a dose of thyroid medication, or excess iodine from contrast dye or supplements. Your doctor uses antibodies or a scan to tell these apart.
Yes. High-dose biotin, often found in hair, skin and nail supplements, interferes with several thyroid assays and can produce a convincingly abnormal set of results in someone whose thyroid is normal. If you take biotin, mention it; your doctor may advise pausing it for a short period before the sample.
TSH alone is often used for a first check, because it tends to shift before the hormones do. The full profile adds free T4 and free T3, which show how severe a problem is and reveal unusual patterns that TSH alone would miss, such as a pituitary problem, the effects of serious illness or assay interference. It is also useful when adjusting thyroid medication.
Not straight away. TSH lags behind change, so results drawn soon after a dose adjustment may not yet reflect the new state. Your doctor will set the interval, usually some weeks, and it helps to test at a similar time of day and in the same laboratory each time, since free hormone results are method-dependent.
TSH is the pituitary's instruction to the thyroid. When hormone output falls, the pituitary raises the volume of that instruction, so TSH climbs. The two moving in opposite directions is the expected pattern in an underactive gland.
It is usually better to take it afterwards. A dose absorbed shortly before the draw raises free T4 for several hours and can make a correct dose look excessive. Take your tablet as soon as the sample is done.
Only the unbound fraction can enter cells and do anything. Pregnancy, some contraceptives and liver disease change how much carrier protein is in the blood, which shifts the total while leaving the free hormone (and the actual thyroid function) unchanged.
That combination is common and is often described as subclinical. Your doctor will usually want the test repeated after an interval, along with thyroid antibodies, before deciding whether anything needs treating, because a single reading can be a passing fluctuation.
No fasting is needed and the sample can be taken at any time, though a morning appointment makes repeat results easier to compare. If you take levothyroxine, take that morning's dose after the blood has been drawn, not before.
The free thyroid profile test is AED 149, including a physician-reviewed report, with results usually within 24 hours. Home collection anywhere in Dubai is free when your order reaches AED 300 or includes a package; below that, a AED 100 home collection fee applies (AED 50 for a lab walk-in).