Home kit
TSH Thyroid Test
Thyroid stimulating hormone on its own, the single most sensitive first-line thyroid test.
- Doctor-reviewed results
- Laboratory analysis
- 1 to 2 working days from lab receipt
- No fasting required
What’s included
1 marker measured
TSH
Thyroid-stimulating hormone, released by the pituitary gland to prompt the thyroid to make T4 and T3. Thyroid hormone levels feed back to control it, so a TSH above the normal range points to an underactive thyroid, especially when free T4 is low.
Overview
TSH moves before the thyroid hormones themselves do, which makes it the most sensitive single first-line thyroid test and the one a GP orders first. It is also the usual number to follow if you are watching a borderline result over time.
TSH is the pituitary gland's instruction to the thyroid, and it moves before the thyroid hormones themselves do, which is why it is the test a GP orders first. It varies through the day, so if you are tracking it over time it helps to give the sample at a similar time each go. A slightly raised result with a normal free T4 is usually repeated after three to six months before anything is done, because some come back to normal by themselves.
Who this is for and who it isn’t
Who it’s for
- Adults aged 18 and over
- Anyone feeling cold, tired or gaining weight who wants a first thyroid test
- People following a previous borderline TSH over time
Who it isn’t for
- A TSH on its own cannot describe what the thyroid is doing when it is abnormal, because free T4 is what completes the picture. If you suspect a problem rather than simply want a check, the Thyroid Check covers TSH and free T4 together. Never change a levothyroxine dose on a private result.
- TSH can also mislead during or soon after a serious illness, and if you have a pituitary condition, so it is best tested when you are well. If you have sudden chest pain that does not go away, call 999. If you have a racing or irregular heartbeat, chest pain that comes and goes, or you are losing weight without trying, contact your GP rather than waiting for a test.
- Anyone with a new, severe or worsening symptom: contact your GP or call NHS 111. A test you buy today is not a substitute for being examined.
Common reasons people choose this test
- Feeling cold, tired or gaining weight without a clear reason
- Feeling unusually hot or sweaty
- Following a previous borderline TSH
- Thyroid disease in a parent, brother or sister
- Hair thinning or dry skin you want a thyroid check for
These are reasons people choose to test, not signs that something is wrong. A result is one part of a picture your doctor puts together with your history and an examination.
What your result looks like
Every result is shown with the unit and the reference range exactly as the laboratory reported it, with the doctor’s note underneath.
- TSH▲ High
- Result
- 5.6 mIU/L
- Range
- 0.27–4.2
| Marker | Result | Units | Range | Flag |
|---|---|---|---|---|
| TSH | 5.6 | mIU/L | 0.27–4.2 | ▲ High |
Doctor’s note (example)
TSH is slightly raised with a normal free T4, a pattern doctors describe as subclinical. About half of these settle on their own, so guidelines repeat it in three months before considering treatment.
Values above are examples. Your report shows your own results with the laboratory’s units and reference range for your age and sex, reviewed, signed and released by a GMC-registered doctor.
How it works
- Your kit arrivesPosted to your door, with instructions and what you need to send your sample back.
- You take your sampleFinger-prick sample at home, or a clinic blood draw, your choice
- The laboratory analyses itYour sample is processed for the measurements included in this test. Lab processing typically takes 1 to 2 working days from receipt of your sample.
- A doctor reviews and releases itA GMC-registered doctor reads every result and signs the report before it reaches you.
- Sample
- Home finger-prick kit
- Preparation
- No fasting required
- Who it's for
- Any sex · ages 18+
How to prepare
What we can and can’t tell you
The reference range beside each result is the laboratory’s own. A result in range is not a clean bill of health and a result outside it is not a diagnosis. Most ranges cover about 95% of healthy people, so about 1 in 20 healthy people fall just outside any one range. No test result replaces an examination or your own doctor’s judgement, and none of these panels is a cancer screening programme.
Read the full note
The reference range printed beside each of your results is the laboratory's own, and it is the range that applies to your result. We do not apply a second range of our own, and we do not tell you that a result the laboratory reported as normal is nonetheless too low or too high. If you see a claim elsewhere that your result ought to sit inside a narrower band than the one the laboratory printed, treat it with caution and ask your doctor.
Some assays cannot give an exact figure above or below a certain point, and those results are reported the way the laboratory sends them, for example as a value greater than a stated number. A result in range is not a clean bill of health, and a result outside a range is not a diagnosis: most reference ranges are set to cover about 95% of healthy people, so some healthy people fall just outside them. No blood test replaces an examination, a scan or your own doctor's judgement, and none of these panels is a screening programme for cancer.
If you have a symptom that is new, severe, or getting worse, contact your GP or NHS 111 rather than waiting for a test result. In an emergency call 999.
Frequently asked questions
Does the time of day matter?
Somewhat. TSH varies through the day, so if you are following it over time, sample at a similar time each go.
Do I need to fast?
No. A non-fasting sample is fine. If you are following results over time, try to sample at a similar time of day each go.
My TSH is slightly raised. What happens next?
A slightly raised TSH with a normal free T4 is common, and some settle on their own. That is why UK guidance repeats it, usually after three to six months, before any treatment is considered. The reviewing doctor explains where yours sits.
Does biotin affect thyroid results?
It can. High-dose biotin, often found in hair and nail supplements, can make thyroid results falsely high or low. Tell us if you take it, and ask your pharmacist or GP whether to pause it before your sample.
How long do results take?
The laboratory typically takes 1 to 2 working days from receiving your sample. This does not include kit delivery, sample collection or return postage. A doctor reviews your results before they are released.
Can I choose a home kit or a clinic?
Both, it is your choice at checkout. Either collect a finger-prick sample at home with the posted kit and send it back as the instructions explain, or book a clinic appointment and have a trained clinician take the sample for you.
Is a doctor involved?
Yes. Every result is reviewed by a GMC-registered doctor who signs it off and explains what it means and what to do next.
Is it confidential?
Your results are available through your secure patient portal. Our privacy policy explains how your information is handled and when it may be shared to provide your care.
What happens to my sample and results?
Your sample is analysed at a UKAS-accredited laboratory (ISO 15189). A GMC-registered doctor then reads every result and signs the report before it is released, so nothing reaches you unreviewed. There is no option to receive results without a doctor reading them first. The report arrives in your secure portal in plain English: each result with its unit and the laboratory's own reference range, and the doctor's note on what the set means read together. If a result sits outside its range the report says so and explains what usually happens next, which is most often a conversation with your own GP, who can act on it alongside your history and examination. Most reference ranges are set to cover about 95% of healthy people, so about 1 in 20 healthy people fall just outside any one of them. On a report with many results it is common for one to sit just outside its range, and a single number on its own rarely tells the whole story. If a result needs urgent attention, the reviewing doctor is alerted straight away and we contact you by phone the same working day rather than leaving it in the portal for you to find. If a specific result needs rechecking, the reviewing doctor says so in your report.
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