Vitamin D (25-OH) Blood Test

Vitamin D (25-OH/D3) Blood Test

Vitamin D is a fat-soluble vitamin essential for healthy bones, hair, and skin, as well as overall immune function. Adequate levels are linked to a lower risk of heart disease, better blood pressure regulation, reduced inflammation, and improved muscle strength and function. Deficiency can lead to muscle weakness, pain, and increased risk of certain autoimmune conditions such as multiple sclerosis, rheumatoid arthritis, and type 1 diabetes.

The body produces vitamin D in the skin when exposed to sunlight, particularly in its active form, D3. It can also be obtained from dietary sources such as fatty fish (e.g., salmon, mackerel), fortified foods (e.g., milk, cereals), and supplements. Maintaining a balance of sun exposure, diet, and supplementation helps ensure optimal vitamin D levels.

This blood test measures your vitamin D status, providing valuable insights into your bone health, immune function, and overall wellbeing.

If you’re not sure exactly what you need, we advise all our clients to consult with a GP or one of our Registered Nutritionists before taking any blood tests. However, below you can find more information about this panel, and we hope it will help.

IS THE VITAMIN D (25-OH) BLOOD TEST RIGHT FOR ME?
Vitamin D supports immune function, helping the body fight infections, and is involved in regulating cell growth and differentiation. Deficiency has been linked to higher infection risk and may play a role in preventing certain cancers, though further research is ongoing.

Why Have the Vitamin D (25-OH) Blood Test?
Maintaining adequate vitamin D levels may support a longer lifespan and reduce the risk of chronic diseases — making this test a valuable check for your overall health and wellbeing.

SYMPTOMS AND TAGS

Aches, Bones, Chronic fatigue, Fatigue and Hair loss

1. Fill out the contact form on the main page
2. Choose your preferred panel
3. Select between a Home Kit (via post), a Clinic Appointment, or VIP service
4. Make the payment online.
5. We'll contact you to arrange a clinic appointment or a VIP service and email you with your home kit delivery details.

Not sure which panel or test is right for you? Reach out to one of our Registered Nutritionists  

COLLECTION OPTIONS

1. VIP: Home/Office/Hotel visit by our phlebotomist – Available in London UK only (1-3 days)
2. Clinic visit (24+ UK locations, 1-3 days)
3. At-home kit (3-6 days)

VIP Phlebotomist Visit (London Only):

Perfect for busy individuals or corporate teams.

• Available across London.
• Once payment is received, our team will contact you to arrange your appointment — usually the same day if booked before 10 am, or the next day if later.
• Additional patients beyond 10 are charged £25 each, invoiced after the visit.
• Please select the total number of blood tests at checkout so our phlebotomist can bring the right equipment.
• Your blood will be collected by a trained phlebotomist and delivered directly to our lab for fast, accurate results.

In-Clinic Appointment:

Quick, professional, and convenient.

• Same or next working day appointment.
• We’ll contact you within 60 minutes of booking to arrange your visit.
• Your blood will be collected by a trained phlebotomist and sent directly to our lab for fast, accurate results.
• Choose your nearest clinic and skip the wait. (Check Locations)

Home Kit:

Test from the comfort of your home — anywhere in mainland UK.

• Everything you need to collect your sample in about 15 minutes.
• Return it to our lab via Prepaid Royal Mail  Tracked 24.
• Free replacement kit if anything goes wrong or more blood is needed — so you can order with confidence.

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.

Clinic appointment - how to prepare for the Vitamin D (25-OH) Blood Test

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

• Read the instructions in the SPECIAL INSTRUCTIONS section
• 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 - how it works with the Vitamin D (25-OH) Blood Test

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!

Vitamin D (25-OH) 

We always encourage you to visit one of our Cliniques for any of our blood tests.

HOME KIT VIA ROYAL MAIL TRACKED 24

This service costs additional £19.00 and includes:

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.

CLINIC APPOINTMENT - SAME OR NEXT WORKING DAY

This service costs additional £38.00 and includes:

• No waiting. We will call you within 2 hours to book your appointment for the same day when purchased before 10am or following day if later than 10am.
• Quick blood collection from your vein, by our professional phlebotomist.
• Blood transported directly to our laboratory - for quick and accurate results.

No home kit exclusion for this panel. We always recommend an in Clinique appointment when the time permits.

We are extremely fast, with some results available within hours and others within a working day or less, from the time your sample is in our lab. However, this is not a guarantee and should not be taken as such. This is the guideline turnaround time that can be shorter or longer.

THIS IS NOT A GUARANTEED TURNAROUND TIME.

We are extremely proud of our very short turnaround times and very efficient laboratory processes; you will receive your results as soon as they are available and have completed clinical validation.

Whilst we accommodate the shortest time scales, with some results available within hours, for some tests the turnaround time is 3-4 working days.

DR. ADAM STATEN - GP VIEW AND RED FLAG SYMPTOMS

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.

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.

Can I see a GP to discuss my Results?

Yes, usually the same or next day.

Our fantastic partner clinical team of consultants and GPs. Once you have your results, you can book an online video consultation to discuss your results.

Our clinical team consists of practicing NHS and private GPs, who work closely with our laboratory and can tell you what your blood test results mean for you. Having an integrated laboratory and GP services makes your health journey seamless and extremely efficient.

This service is not included in the price of the test, it is charged separately, should you wish to book it.

Will I have a general explanation of my results?

Yes, our doctors put a huge amount of effort into your online Health Dashboard, which will have explanations of what each biomarker is, the normal reference ranges and what it means if you are outside of them.

QUICK AND ACCURATE RESULTS DIRECT FROM THE LABORATORY.

We partner with regulated laboratories and accredited clinics that manufacture their own approved home sample collection kits. Your results are looked after by our fantastic clinical governance team and a 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.