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HomeTests ExplainedThyroid Test

BLOOD TEST · SMART CARE POLYCLINIC, DEIRA

Thyroid Test explained

Checks whether your thyroid is running fast, slow or normally — the gland that sets your metabolic pace.

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SAMPLE
Blood
FASTING
Not needed
INCLUDED IN
7 packages
WHERE
29 Doha Centre, Al Maktoum Rd, Deira

What the Thyroid Test measures

TSH is the message the brain sends the thyroid. When the thyroid is underactive the brain shouts louder and TSH rises; when it is overactive the brain goes quiet and TSH falls. A thyroid profile adds the hormones the gland itself makes. How those results are interpreted, and when an underactive thyroid warrants treatment, follows American Thyroid Association guidance.1

What the result tells you

High TSH — an underactive thyroid

Everything slows: tiredness sleep does not fix, weight gain without eating more, feeling cold, dry skin, constipation, low mood. Treated with a daily tablet.

Low TSH — an overactive thyroid

Weight loss, a racing or irregular heartbeat, tremor, heat intolerance, anxiety and poor sleep. Treated rather than watched, because of the effect on the heart over time.

Borderline, with normal thyroid hormones

Common and often unalarming. Usually repeated after a few weeks rather than treated, since it can settle on its own — particularly after an illness.

Easily distorted

Biotin supplements interfere with the measurement itself and can produce a thyroid result that is simply wrong. Stop them several days before.

How to prepare

Fasting
Not needed
Best time
Any time, but before your morning dose if you take thyroid medication
Avoid before
  • Biotin supplements for at least 3 days
Worth knowing
Tell the nurse if you already take thyroid medication, so the number reflects your own thyroid rather than the tablet.

What can move the result

A result outside the usual range does not on its own mean something is wrong. These are the everyday explanations a doctor considers first.

Thyroid conditions, which often run in families
Pregnancy and the months after birth
Steroids and lithium
A recent severe illness, which moves TSH temporarily
Biotin supplements, which interfere with the measurement

Frequently asked questions

TSH is the message the brain sends the thyroid. When the thyroid is underactive the brain shouts louder and TSH rises; when it is overactive the brain goes quiet and TSH falls. A thyroid profile adds the hormones the gland itself makes. How those results are interpreted, and when an underactive thyroid warrants treatment, follows American Thyroid Association guidance. High TSH — an underactive thyroid: Everything slows: tiredness sleep does not fix, weight gain without eating more, feeling cold, dry skin, constipation, low mood. Treated with a daily tablet.

Sources

Written from current guidance and reviewed 31 August 2026.

Sources cited above

  1. Jonklaas J, Bianco AC, Bauer AJ, et al.. Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid. 2014;24(12):1670-751. PMID 25266247. doi:10.1089/thy.2014.0028The American Thyroid Association guideline on interpreting thyroid function tests and treating an underactive thyroid.

Sources are listed for the specific statements they support. They are published research and guidance, not a substitute for a consultation — what applies to you is decided by a doctor who has assessed you.