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Vitamin D (25-OH) Blood Test

Original price £37.00 - Original price £37.00
Original price
£37.00 - £37.00
Current price £37.00

Vitamin D is a fat-soluble vitamin essential for maintaining bone health, regulating calcium and phosphorus levels in the body, and supporting immune function.

  • Biomarkers: 1
  • Turnaround: 3 days

Simple and accurate blood test from a laboratory you can speak to.

Step 1. Choose sample collection option

Currently selected option: HOME KIT via Royal Mail Tracked 24

  • Available everywhere in mainland UK.
  • Includes everything you need to take a safe and suitable blood sample in about 15 minutes.
  • Post the sample back to our laboratory via Royal Mail Tracked 24.

Re-test guarantee

About the Vitamin D (25-OH) Blood Test

Vitamin D is a fat-soluble vitamin that plays a crucial role in various physiological processes in the human body. Vitamin D is produced in the skin when it is exposed to sunlight and manifests itself in the more biologically active form of D3.

Apart from being essential for healthy bones, hair and skin, adequate vitamin D levels are associated with a lower risk of heart disease. It may help regulate blood pressure and reduce inflammation.

Vitamin D is important for muscle strength and function, and deficiency can lead to muscle weakness and pain. Finally, it is important in managing autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, and type 1 diabetes - these have all been linked to low vitamin D levels.

Vitamin D can be obtained through dietary sources such as fatty fish (e.g., salmon and mackerel), fortified foods (e.g., fortified milk and cereals), and supplements. However, the body can also produce vitamin D when the skin is exposed to sunlight. Therefore, a balance between sun exposure, diet, and supplements can help ensure sufficient vitamin D levels in the body.


    For most biomarkers our usual turnaround time is 24-48 hours, or less, from the time your sample is in our lab. We do not wait for all the results to complete before sending them to you, so you may start receiving results the same day for most cases, or as results become available.

    We are extremely proud of our very short turnaround times and a very efficient laboratory processes. Whilst we accommodate the shortest of time scales, with some results available within hours, for this particular test the usual turnaround time is:

    3 days

Doctor's notes

Hi, I am Dr. Adam Staten and here's my view on this test as a GP and Clinical Director at One Day Tests.

Vitamin D is essential for the absorption of calcium and phosphate from the gastrointestinal tract. These minerals are critical for maintaining strong and healthy bones. Without enough vitamin D, the body cannot absorb enough calcium, leading to weakened bones and conditions like rickets in children and osteoporosis in adults.

Red flag symptoms for the Vitamin D (25-OH) Blood Test

Even if your levels of Vitamin D are normal or low, you should always consult your GP before taking any supplements.

Your Results and Health Dashboard

The results of your Vitamin D (25-OH) Blood Test will be emailed to you as a secured PDF file, ready for your GP and will also be uploaded to our Health Dashboard area of the website. It’s a unique and powerful tool, powered by our in-house clinical analysis research, to match your biomarkers across test panels and symptoms, as well as provide clinical commentary on all individual biomarkers you tested for.

The health dashboard will also provide "panel level" commentary - a birds eye view of the biomarkers that were tested. This feature allows you to view your test results and clinical commentary, and compare them to previous results, giving you a clear understanding of how your health is progressing.

By using the Health Dashboard, you can identify changes in your biomarkers and make necessary adjustments to your lifestyle. This added value is immense, as it empowers you to monitor your health and make informed decisions about your well-being.

It's free and is available with all of our tests.

Save on continuous monitoring with our subscription plan

The best way to look after your health is to do so regularly. This is easy to do with our continual monitoring plans which give you a discount on future blood tests. You choose the frequency and we'll do the rest.

When you purchase a subscription, we will deliver your home test kits or allow you to book appointments in line with your chosen frequency. You will be able to track your biomarkers over time in our powerful Health Dashboard, where results will be automatically updated for you. There is a minimum of 3 tests with any subscription, after which you can pause/restart/cancel at any time.

Special instructions

Hi, I am Stefania Brown, I am the Laboratory Manager at One Day Tests and here are the lab's special requests for the Vitamin D (25-OH) Blood Test.

There are no special instructions for this test, you can take it anytime.

It is important to note that excessive vitamin D intake can lead to toxicity, so it's advisable to consult with a healthcare professional before taking high-dose supplements. Additionally, individual vitamin D requirements can vary, so it is essential to monitor your levels through blood tests if you have concerns about deficiency or excess.

Venepuncture appointment - how to prepare

If you are coming into one of our clinics for the test, this is what you need to do before you arrive:

  • Drink plenty of water about an hour before the appointment.
  • Avoid coffee/tea/energy drinks. Water is good!
  • That’s it! We’ll do the rest.

Home test kit for Vitamin D (25-OH) Blood Test - how it works

Our blood test kits are simple and convenient.

The most important step in doing a blood test at home is to read the instructions very carefully. The process is very simple, but there are a few pitfalls you need to be aware of - you will save yourself a lot of time if you do it right the first time around!

  • Full printed instructions will arrive with your kit - please read them carefully.
  • Drink plenty before taking the sample and warm your hands up in the sink with warm water for a few minutes. This will make your blood flow much better.
  • Fill the tubes to the top line. We don’t need much blood; filling tubes to the top line is about 15 drops of blood.
  • Post the samples on the same day you take them, before midday, Monday to Thursday. If you post it any other time it might get to us late or be stuck at a sorting office over the weekend. You will then have to do it again.
  • Package the sample in the same box the kit came in. Otherwise, Royal Mail or DPD will reject it. The sample tubes go into a pouch, then into a cardboard box, and then into a return envelope. All of this is provided in the kit: please use it.

We look forward to receiving your sample in our lab!

How the finger prick home test kit for Vitamin D (25-OH) Blood Test works - from Dr. Adam Staten

Why choose us?

Hello! My name is Dr. Vinesh Mistry, I am part of the GP team here at One Day Tests and here is why you should trust us to test your blood.

We run our own regulated laboratories and our own accredited clinics. We manufacture our own approved home sample collection kits. Your results are looked after by our fantastic clinical governance team and our super-talented biomedical science team.

When you book your test with us - you book directly with the lab. This means accuracy and responsible duty of care, direct access to the provider and extremely fast turnaround times.

Finally, our customer services rock! You can ask the lab a question any time or you can speak to a real human. It's good to WhatsApp, email on or give us a call on 0845 527 07 67.

Frequently Asked Questions

Hi, I am Lana Nela, Lead Nurse, and here is what we are frequently asked about this test.

Is vitamin D important in therapeutic areas?

Some studies suggest that vitamin D may have a role in mood regulation, and deficiencies have been linked to conditions like depression and seasonal affective disorder (SAD).

Why is Vitamin D important alongside calcium?

Vitamin D helps maintain proper levels of calcium in the blood, which is crucial for muscle function, nerve transmission, and blood clotting.

Why take this test?

Hi, I am Dr. Marco Esposito and here is why it's important to take this test.

Some research suggests that maintaining adequate vitamin D levels may be associated with a longer lifespan and reduced risk of chronic diseases.

Is this test right for you?

Hi, I am Sandeep Patel, I am the Laboratory Director at One Day Tests. Here are the symptoms that you may wish to address with this test.

Vitamin D plays a role in supporting the immune system. It helps the body fight off infections and illnesses, and deficiencies in vitamin D have been associated with an increased risk of infections.

Vitamin D is involved in regulating cell growth and differentiation. It may have a role in preventing the development of certain cancers, though more research is needed in this area.


    Aches, Bones, Chronic fatigue, Fatigue, and Hair loss

Why blood tests are important.