Reference ranges
| Normal | 0.4 – 4.0 mIU/L |
| High TSH | Suggests an underactive thyroid (hypothyroidism) |
| Low TSH | Suggests an overactive thyroid (hyperthyroidism) |
| Pregnancy | Narrower ranges apply by trimester |
Reference ranges vary between laboratories and methods. Always read your result against the range printed on your own report.
Seek care urgently if
- Palpitations with chest pain
- Severe tremor with fever and confusion
- Rapid unintentional weight loss
- Neck swelling with difficulty breathing or swallowing
- Extreme drowsiness with a very high TSH
What a high result can mean
Hypothyroidism
The commonest cause. Fatigue, weight gain, feeling cold, dry skin.
Hashimoto's thyroiditis
Autoimmune damage to the thyroid — the leading cause worldwide.
Iodine deficiency
Still relevant in parts of Nigeria.
Recovering illness
TSH can be transiently raised after acute illness.
Under-treated known hypothyroidism
Suggests the dose needs review.
What a low result can mean
Hyperthyroidism
Weight loss, palpitations, heat intolerance, tremor.
Graves' disease
The commonest cause of an overactive thyroid.
Toxic nodule
A single overactive lump in the gland.
Over-treatment
Too high a dose of thyroid replacement.
Early pregnancy
TSH normally dips in the first trimester.
Have your result in front of you?
Send us the value and we will tell you whether it needs an appointment or not. No account, no form.
Ask about my TSH resultNothing is stored on this website.
What happens next
TSH alone is a screening result. Free T4 — and sometimes T3 — establishes how significant it is. A thyroid ultrasound is added where the gland is enlarged or a nodule is felt.
Thyroid Function Test Thyroid Ultrasound Full Blood CountOther results people look up
This page explains what a result can mean in general terms. It is not a diagnosis and cannot account for your history, medication or examination. All visits to Mascot Healthcare are by appointment — Mon–Sat, 9AM–5PM, 52 Sholanke Street, Akoka, Yaba, Lagos.