Blood sample collection options

You can choose your preferred collection method when you checkout

Finger prick kit (FREE)

You can do this test at home without the need for a doctor. We'll send you everything you need to collect your sample and post it back to us. And it's all included in the cost. We've put together a video that covers the process, making it easy to check and track your health from home.

Home nurse appointment (+£45) was £60

We'll arrange for a medical professional to visit your home and collect your sample. This is great if you're unsure on how it all works or have trouble collecting a sample. No need to book a doctor's appointment or visit a clinic, we'll send you everything you need to collect a sample and post it back to our labs.

Visit a partner clinic (+£45)

Once you've ordered your test, look out for an email from our phlebotomy partners containing information and a link to book your appointment. We'll send you everything the clinic will need to complete the sample and post it back to our labs.

Organise a nurse myself (FREE)

If none of the above options work for you, you can arrange your own medical professional to collect your sample. There is no additional charge for this. Once you've ordered your test, we'll send you everything you and your chosen medical professional will need to collect a sample and post it back to our labs.

Still unsure how it works? You can find more information on collection methods and the service we provide in our 'How it Works' section.

What gets tested?

1 Biomarker

Additional biomarkers can be added by personalising this test.

What are biomarkers?

Biomarkers are specific compounds we can detect in your blood sample that reflect different things about your health. Your test will tell you your levels for each of the above biomarkers, and whether they are in a normal range.

About flexible subscriptions

How does a subscription work?

When you purchase this test subscription plan, we will automatically send you another test kit in a few months. Don't worry - you have full control over when this will be, and you can change/cancel it anytime.

When you first purchase this test, you can choose your subscription options in the checkout. We do this, because we recommend taking multiple tests over time to track how your biomarkers change. You'll be charged per test kit (rather than monthly, for example).

Why subscribe to multiple tests?

One test will show you what areas you need to focus on, continued testing will help you learn how your training, diet and lifestyle is impacting your health.

How often should I test?

We recommend a follow up test 3 months after your first test, followed by a test every 6 months depending on your results, but its up to you!

Can I change what's tested in future tests?

Yes, you can tailor/customise subsequent tests (via your app) to focus on just the areas that need improving.

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Vitamin B12 Blood results are your fingertips
Hand holding a lancet up to a finger on the other hand
Vitamin B12 Blood test, Track your health
Vitamin B12 Blood results, Compare yourself with others
Analysed by
NHS Lab
Tracked 24
delivery
Personalised
GP advice
Finger prick or venous collection

Vitamin B12 Blood Test

Trustpilot 4 stars

Results in 2 working days

1 Biomarker

Our Vitamin B12 Blood Test helps you check your active B12 levels from home with a quick and easy finger-prick test. Vitamin B12 is essential for energy, brain function, and nerve health. Low levels can cause fatigue, memory issues, and even long-term nerve damage. This test is ideal for vegetarians, vegans, or those at risk of deficiency. Get accurate lab-tested results and expert insights to take control of your health.

Analysed by
NHS Lab
Tracked 24
delivery
Finger prick or venous collection

£50

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What gets tested?

1 Biomarker

Blood sample collection options

1 Million+

results delivered

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What does a vitamin B12 test check?

A B12 vitamin deficiency can make you feel extremely tired and lacking in energy. Taking this Active B12 home blood test is the best way to identify how much vitamin B12 is available for your body to use. It’s different from a total B12 test that measures the total amount of B12 stored in the body.

Home vial icon

How to check vitamin B12 levels at home

We’ve made our vitamin B12 blood test easy to do from the comfort of your home. The kit contains everything needed to collect a small amount of blood and post it back to our labs for analysis. You’ll get the results within 2 working days of your sample reaching our labs, along with comments and advice from our medical team.

Vial with magnifying glass

What causes vitamin B12 deficiency?

Vitamin B12 deficiency can result from factors such as a bad diet, malabsorption due to conditions like pernicious anaemia or gastrointestinal disorders, certain medications that interfere with absorption, or insufficient production of intrinsic factors needed for B12 absorption in the stomach.

Vial-Info

What's the difference between active B12 and total B12?

Active B12, or holotranscobalamin, is the biologically active form of vitamin B12 that is readily available for cellular uptake. Total B12 includes both active B12 and inactive forms (bound to haptocorrin). Measuring active B12 provides a more accurate assessment of B12 status and potential deficiencies.

How our Vitamin B12 Blood Test works

Getting the insights you need to improve your health has never been easier.

A Hand holding a lancet that is held up to a finger on the other hand

1. Collect your blood sample

It takes 5 minutes to collect a small sample of blood from your finger tip. Post it back to our labs using the Tracked-24 envelope included in your kit.

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2. View your results

You will receive your Results within 2 working days in the Forth app, along with the optional doctors comment and detailed report.

Metabolic health scores

3. Make improvements

The detailed report makes it easy to identify areas that need improving, make changes and track your progress.

Vitamin B12 Blood Test, recommended by our doctors

"B12 is crucial for making red and white blood cells, repairing cells, and synthesising new DNA. It can't be produced in the body and must be supplied by the diet. Foods rich in vitamin B12 are usually animal based, so this test is particularly useful if you're following a vegetarian or vegan diet. We focus on the active form of B12 giving greater insight into your functional levels."

Dr Thom Phillips

Dr Thom Phillips

Clinical lead

Frequently asked questions

This is what our customers ask us about the most. For more information, try our help centre.

What is vitamin B12?

Active B12 is the bioavailable form of vitamin B12—meaning it is the fraction of B12 that is readily absorbed and used by the body’s cells. Unlike total B12, which includes inactive forms that the body cannot utilise, active B12 is the best marker for assessing true B12 status.

Vitamin B12 is essential for:

  • Energy production – Supports metabolism and reduces fatigue.
  • Red blood cell formation – Helps prevent anaemia and maintains oxygen transport.
  • Nervous system health – Protects nerve cells, preventing neurological damage.
  • Brain function – Supports memory, concentration, and mental clarity.
  • DNA synthesis – Plays a key role in cell growth and repair.

What is a normal b12 level?

The labs we use to analyse blood samples use a healthy range of 38-188pmol/L for active b12. Data from Forth customers shows the median active b12 level for men and women is 90 and 86 pmol/L respectively, with 88% of UK adults have a level in the healthy range.

Can vitamin B12 deficiency be a sign of cancer?

While B12 deficiency can be linked to various health conditions, including certain cancers, it is usually caused by dietary intake or absorption issues. A blood test can help identify the cause.

What causes B12 deficiency?

Common causes include poor diet (especially in vegetarians and vegans), pernicious anaemia, digestive disorders (like Crohn’s or coeliac disease), and long-term use of certain medications.

Can B12 be too high?

Yes, high B12 levels can occur due to supplementation or underlying health conditions such as liver disease or kidney dysfunction. A test can help determine if further investigation is needed.

What other markers should I test with active B12?

For a complete picture of your health, consider testing biomarkers that work closely with vitamin B12 in energy metabolism, nerve function, and overall well-being:

  • Folate (serum) – Works with B12 to support red blood cell formation and DNA synthesis. Low folate can worsen B12 deficiency symptoms.
  • Ferritin – Measures stored iron levels. Low iron, along with B12 deficiency, can contribute to fatigue and anaemia.
  • Red Blood Cell (RBC) Count & Haemoglobin – Helps assess if B12 deficiency is affecting red blood cell production, leading to anaemia.
  • Magnesium (serum) – Supports nerve function and energy production, working alongside B12 to maintain healthy muscles and nerves.
  • Vitamin D (25 OH) – Works with B12 for energy and immune function. Deficiencies in both can contribute to fatigue and weakness.

How long to recover from vitamin B12 deficiency?

Recovery time depends on the severity of deficiency and treatment method. Many people feel improvement within a few weeks, but full recovery can take several months.

What foods contain vitamin B12?

B12 is found in animal-based foods such as meat, fish, eggs, and dairy. Fortified foods, like plant-based milks and cereals, are good options for vegetarians and vegans.

How long does it take to get my results?

Once your sample reaches our lab, you’ll receive your results within 2 days via your secure online account.

When would I need a B12 injection?

B12 injections are typically needed for severe deficiency or if you have conditions like pernicious anaemia or malabsorption issues where oral supplements are ineffective.

Is your packaging discreet?

Yes, all our test kits are delivered in plain, unbranded packaging to protect your privacy.

How soon will the test arrive?

If you order before midday (Mon-Fri), your test kit will be dispatched the same day and should arrive within 1-2 working days.

How secure is my data?

We use industry-leading encryption to protect your personal information. Your results are private and only accessible through your secure account.

Can I have someone take my blood for me?

Yes, you can choose your collection method after adding the vitamin b12 test to your basket.

How soon will the test arrive?

If you order your test before midday on a Monday to Friday then your kit will be dispatched the same day.

All our kits are sent out via Royal Mail Tracked24, so it should be with you within 1-2 working days.

How secure is my data?

We have strict processes in place to ensure the protection of your data. Following GDPR the company also operates under tight legal rules about the sharing of data which ensures that data is only shared if it is crucial to the delivery of our service. For example, our doctors see customer results at the time of review, however, after review, access to results is withdrawn.

Learn more about your data security.

Can I have someone take my blood for me?

Yes. We offer two options if you do not want to do our finger prick test. The first is a home appointment where a nurse comes to your home to take a blood sample. The second is to visit a Phlebotomy clinic near you that offers a blood sample service.

A blood sample will be taken from your vein and we will provide you with everything you need to give to the nurse to allow them to take the sample.

The nurse will give you the blood sample to return to us using the pre-paid envelope provided.

Does a doctor review my results?

We have a team of doctors and nurses who look at all results and will comment on any results that are outside of the normal range for your age.

Can I download the results to share with my GP?

Yes, you can download your results from your health dashboard as a PDF to share with your GP.

Learn how to export your results.

We are dedicated to supporting you on improving your health

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What customers say about our Vitamin B12 Blood Test

Vitamin B12 Blood Test