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Intel Lab Diagnostics Dubai
Single Biomarker

Thyroid Stimulating Hormone (TSH)

Thyroid Function Screen

TSH is the most sensitive test for thyroid function. Produced by the pituitary gland, it controls thyroid hormone production. High TSH suggests hypothyroidism, while low TSH suggests hyperthyroidism.

BLOOD24 HOURSNO FASTING
AEDAED149
  • Free home collection
  • Physician-reviewed report

24 Hours

Turnaround

Blood

Sample

About This Test

What the Thyroid Stimulating Hormone (TSH) test tells you

Thyroid stimulating hormone, usually shortened to TSH, is not made by the thyroid at all. It is released by the pituitary gland at the base of the brain, and its job is to tell the thyroid how much hormone to produce. Because the pituitary is constantly sampling how much thyroid hormone is circulating and adjusting its signal accordingly, TSH behaves like a thermostat reading for the whole system rather than a measure of the gland itself.

That relationship is an inverse one, which surprises many people the first time they see a report. When the thyroid is underactive and hormone levels drift down, the pituitary pushes harder and TSH rises. When the thyroid is overactive, the pituitary backs off and TSH falls, sometimes becoming almost undetectable. The signal is also amplified: a small change in circulating thyroid hormone produces a proportionally much larger change in TSH, which is why TSH usually shifts before free T4 or free T3 look abnormal at all.

In practice this makes TSH the natural first test when thyroid disease is suspected, and the test most often repeated when someone is taking thyroid medication. A doctor will normally interpret it alongside free T4, and add free T3 or thyroid antibodies when the picture needs filling in. TSH is not infallible (it assumes the pituitary itself is working normally, and it lags behind rapid changes in thyroid status by a matter of weeks), so a single value is read in the context of your symptoms, your medication, and any other illness you happen to have at the time.

Sample type
Blood
Measured in
mIU/L
Turnaround
24 Hours
Fasting
Not required
Best for
Adults
Why Get Tested?

First-line screening for thyroid disorders. Recommended for anyone with fatigue, weight changes, temperature sensitivity, or a family history of thyroid disease.

  • First-line thyroid screen

    TSH is the single most informative starting test when thyroid disease is suspected, because it changes earlier and more dramatically than the thyroid hormones themselves.

  • Explaining vague symptoms

    Tiredness, weight change, hair thinning, low mood and sensitivity to cold or heat all overlap with thyroid dysfunction. Measuring TSH is a simple way to include or exclude the thyroid as a cause.

  • Adjusting thyroid medication

    When you take levothyroxine or anti-thyroid tablets, TSH is the main number your doctor uses to decide whether the dose is right.

  • Detecting subclinical disease

    TSH can drift out of the usual pattern while the thyroid hormones still look ordinary, flagging a mild problem that may deserve watching rather than treating.

When This Test Is Ordered

Reasons your doctor may request the Thyroid Stimulating Hormone (TSH) 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

    • Persistent fatigue, low mood, or unexplained weight gain or loss.
    • Feeling unusually cold or unusually hot compared with the people around you.
    • Palpitations, tremor, sweating or difficulty sleeping without an obvious cause.

  • Findings on examination

    • A swelling in the front of the neck, or a lump found on examination.

  • Monitoring & pregnancy planning

    • Routine monitoring while taking levothyroxine or anti-thyroid medication.
    • Planning a pregnancy, or early pregnancy, when there is a personal or family history of thyroid disease.
Preparation
The short version
No prep needed.
  • Blood
  • Free home collection
  • No fasting
  • Results in 24 Hours
  1. 1
    Book any time

    No fasting window: pick any slot that suits you, online or on WhatsApp.

  2. 2
    We come to you

    A DHA-licensed nurse collects your sample at home or in the office: free home collection.

  3. 3
    Results in 24 Hours

    A physician-reviewed, easy-to-read report lands securely by WhatsApp and email.

Prep note
Physician reviewed

No fasting is required.

TSH follows a daily rhythm (it is at its highest overnight and in the early morning and dips in the afternoon), so if you are being monitored, try to give your sample at a similar time of day each time. If you take levothyroxine, take that day's tablet after the blood draw rather than before it.

Tell the team about any biotin or high-dose B-vitamin supplements, which usually need to be paused for a few days beforehand, and about steroids, amiodarone, lithium or contrast scans in the recent past. Recent serious illness can shift the result, so testing is generally better done once you have recovered.

Understanding Your Results

A result in the Normal band, 0.4 to 4 mIU/L, means the pituitary is finding enough thyroid hormone in circulation. The relationship is inverse. A result in the High band, 4.01 to 10 mIU/L, means the pituitary is pushing harder and points towards an underactive thyroid: most often autoimmune thyroiditis, an under-replaced dose, or loss of thyroid tissue after surgery. A result in the Low band, 0 to 0.39 mIU/L, points towards an overactive gland or more replacement than you need, and is also seen in early pregnancy. TSH responds slowly, so a sample taken soon after a dose change or an illness may not yet reflect where things have settled; biotin distorts it too. It also assumes a working pituitary: in pituitary disease TSH can look reassuring while your thyroid hormones are genuinely low, so free T4 is read beside it. Your doctor reads the pair with your symptoms and medication.

SmartReport
0.44
Healthy zone2mIU/LNormal
Reference ranges · mIU/L
Low
Low TSH may suggest an overactive thyroid (hyperthyroidism).
0–0.39
Normal
Normal thyroid function.
0.4–4
High
High TSH may suggest an underactive thyroid (hypothyroidism).
4.01–10

Ranges are a guide: your physician interprets your result alongside your symptoms and history.

Reading a High or Low Result

  • What a higher result can point to

    • An underactive thyroid, most often from autoimmune (Hashimoto's) thyroiditis.
    • Thyroid hormone replacement taken at a dose that is not yet sufficient, or taken irregularly.
    • Loss of working thyroid tissue after thyroid surgery or radioactive iodine treatment.
    • Recovery from a serious non-thyroidal illness, when TSH can rebound temporarily.
    • Iodine deficiency, or a large iodine load from contrast media or supplements.
    • Rarely, a pituitary tumour that secretes TSH, or inherited reduced tissue response to thyroid hormone.

  • What a lower result can point to

    • An overactive thyroid, such as Graves' disease or a hormone-producing thyroid nodule.
    • Thyroid hormone replacement at a dose higher than the body needs.
    • The early, hormone-releasing phase of thyroiditis, including thyroid inflammation after pregnancy.
    • Disease of the pituitary or hypothalamus, where the gland cannot generate a normal signal.
    • Early pregnancy, when placental hormones mildly stimulate the thyroid and suppress TSH.
    • Medicines such as high-dose corticosteroids or dopamine, which suppress pituitary output.

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.

Limitations & Safety

What this test cannot tell you

  • TSH assumes a normally functioning pituitary; in pituitary disease it can look reassuring while thyroid hormone levels are genuinely low.
  • It responds slowly, so a value taken soon after a dose change or an acute illness may not reflect where the thyroid has actually settled.
  • High-dose biotin supplements can distort the immunoassay in either direction and produce a misleading result.
  • An isolated abnormal TSH is not a diagnosis on its own, and is normally repeated and paired with free T4 before anything is decided.

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.
Key Points
  • 1TSH comes from the pituitary gland, not the thyroid, and reflects how hard the body is pushing the thyroid.
  • 2The relationship is inverse: a high TSH points towards an underactive thyroid and a low TSH towards an overactive one.
  • 3It usually becomes abnormal before free T4 and free T3 do, which is why it is used first.
  • 4It is the main measurement used to fine-tune thyroid medication doses.
  • 5Results are interpreted with your symptoms and other thyroid tests, never in isolation.
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Frequently Asked Questions

Everything you need to know about the Thyroid Stimulating Hormone (TSH) test. Can't find what you're looking for?

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TSH is the instruction, not the product. When the thyroid is not producing enough hormone, the pituitary detects the shortfall and sends a stronger signal, so the TSH number goes up even though thyroid activity is down.