Home kit
Vitamin D Test
25-hydroxy vitamin D, the standard measure of your vitamin D store, from a finger-prick sample at home.
- Doctor-reviewed results
- Laboratory analysis
- 1 to 2 working days from lab receipt
- No fasting required
What’s included
1 marker measured
Vitamin D (25-OH)
Your vitamin D store, which supports bone, muscle and immune health. Low levels are common in the UK, especially from January to March.
Overview
Between October and early March the UK sun is not strong enough for your skin to make enough vitamin D, so most people rely on what they stored over summer plus whatever their diet and supplements add. Testing tells you whether that is enough. People often test at the end of winter, or because they cover up, have darker skin or spend most daylight hours indoors, all of which make a low level more likely.
Vitamin D is made in the skin from summer sunlight and stored for the months when there is not enough of it, which in the UK is roughly October to March. In the UK, the store built up over summer does not reliably last through winter. The report gives the laboratory's own figure and range, and the reviewing doctor explains where you sit and what UK guidance says about topping it up.
Who this is for and who it isn’t
Who it’s for
- Adults aged 18 and over
- Anyone who wants to check their vitamin D after the winter
- People who cover up, have darker skin, or spend the daylight hours indoors
Who it isn’t for
- A single vitamin D result does not say why it is low. Diet, time outdoors, clothing and skin colour all affect it, and this test cannot tell those apart. It is also not a bone density measurement: if osteoporosis is the question, a DEXA scan arranged through your GP is the route, and the Bone Health Check adds calcium and kidney and liver markers.
- And if you are already taking a high-dose supplement, the number mostly reflects the supplement rather than what your body manages on its own.
- 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
- Wanting to check your level at the end of winter
- Aching bones or muscles
- Spending most of the daylight hours indoors
- Having darker skin or usually keeping the skin covered outdoors
- Already taking a supplement and wanting to know whether it is enough
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.
- Vitamin D (25-OH)▼ Low
- Result
- 32 nmol/L
- Range
- 50–150
| Marker | Result | Units | Range | Flag |
|---|---|---|---|---|
| Vitamin D (25-OH) | 32 | nmol/L | 50–150 | ▼ Low |
Doctor’s note (example)
This illustrative vitamin D result is below the displayed laboratory range. A clinician would consider symptoms, risk factors and current supplements before advising on next steps. Repeat testing is not automatically needed; any follow-up depends on the individual clinical situation.
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
When is the best time of year to test?
Vitamin D tends to be lower after the winter months and higher after summer, so a sample in late winter often shows your lowest level and a late-summer sample your highest. Testing at the same point each year is what makes two results comparable.
Should I stop my supplement first?
That depends on the question you are asking, and it is worth raising with your GP rather than deciding on your own. If you want to know whether your current supplement is doing its job, take the sample while carrying on with it as usual.
What counts as low?
Guidance from the Royal Osteoporosis Society describes a level below 25 nmol/L as deficient, 25 to 50 as possibly not enough for some people, and above 50 as enough for almost everyone. Your report prints the laboratory's own range beside your result, and the doctor's note explains where you sit and what UK guidance suggests.
How long before a repeat is worth doing?
Vitamin D moves slowly, so about three months after a change in supplement is the earliest a repeat is usually worthwhile. How often to test after that is a question for your GP.
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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