Vitamin B12 Blood Test

£69.00

5/5 from 221+ verified Google reviews

Measures total and active B12 levels supporting neurological and haematological health.

Booking details

Overview

A B12 blood test checks how much vitamin B12 (also called cobalamin) is in your blood. Vitamin B12 helps your body make healthy red blood cells and keeps your nerves working properly. Common B12 deficiency symptoms include tiredness, low energy, pins and needles, a sore tongue, memory problems and low mood. Our private B12 test is a quick and simple way to check your B12 levels and find out whether low B12 could be behind how you feel.

What It Measures: Vitamin B12 (cobalamin) levels in a venous blood sample. Looking for active B12 (holotranscobalamin)? See our separate Vitamin B12 Active (Cobalamin) Blood Test.

Who It’s For: Anyone with symptoms of low B12 or B12 deficiency, people following a vegan or vegetarian diet, people with gut conditions such as Crohn’s or coeliac disease, and anyone taking long-term medicines such as metformin.

Preparation: A standalone vitamin B12 test does not usually require fasting. Let us know if you take B12 supplements or have B12 injections, as these can raise your result.

Laboratory Processing: Simple, accurate blood test analysed in a UK laboratory with professional support available if required.

Turnaround Time: Same day or next working day depending on sample timing.

Booking Options: Clinic Visit, Home Visit (Essex only) or Kit Only (Venous Blood Collection). Find a B12 blood test near you using our clinic finder.

Can’t Find Your Test?

If you can’t find the test you’re looking for, simply give us a call and our support team will guide you to the right option. We’re here to ensure you get the correct test quickly and confidently.

For Bookings Call at:
Vitamin B12Also called cobalamin
Venous bloodProfessional blood draw
3 ways to bookClinic Visit, Home Visit (Essex only) or Kit Only
Active B12 optionDedicated holotranscobalamin test also available

What Is a B12 Blood Test?

A B12 blood test checks the level of vitamin B12 in your blood. Vitamin B12 helps your body make healthy red blood cells and keeps your nervous system working properly. Your body cannot make B12 itself, so it relies on food (mainly meat, fish, eggs and dairy), fortified products or supplements.

A private B12 test with Swift Blood Tests gives you a clear result you can act on quickly, whether you are checking for possible B12 deficiency, monitoring your levels or following a vegan or vegetarian diet. You can book a clinic appointment, a home visit if you live in Essex, or a venous collection kit.

What Does This Vitamin B12 Test Measure?

This test measures vitamin B12 (cobalamin) in a venous blood sample. It is a focused vitamin B12 test, not a full nutritional or anaemia panel.

If you specifically want active B12 measured, also known as holotranscobalamin, Swift offers a separate Vitamin B12 Active (Cobalamin) Blood Test. Active B12 is the portion of B12 that is bound to the protein that delivers it to your cells, and some clinicians request it when a standard result is borderline or does not match symptoms.

B12 Deficiency Symptoms: When a B12 Test May Help

Symptoms of low B12 often develop slowly and can be easy to put down to stress or a busy life. Common signs of vitamin B12 deficiency include:

Tiredness and low energyFeeling exhausted or lacking energy even after rest is one of the most common reasons people check their B12 levels.
Pins and needlesTingling, numbness or a "pins and needles" feeling, often in the hands or feet.
Sore, red tongue or mouth ulcersA smooth, sore or unusually red tongue and recurring mouth ulcers can be linked to low B12.
Muscle weaknessWeakness, heavy limbs or problems with balance and coordination.
Memory and concentrationBrain fog, forgetfulness, confusion or difficulty thinking clearly.
Mood and vision changesLow mood, irritability or disturbed vision can also be associated with low B12.
Seek medical advice promptly if you have numbness, problems with balance or walking, vision changes or confusion. Some nerve-related problems can become harder to reverse the longer B12 deficiency goes untreated, so do not wait to book a private test if these symptoms are getting worse.

Who May Be More Likely to Have Low B12?

A vitamin B12 blood test may be worth considering if any of the following apply to you:

Vegan or vegetarian dietB12 is found naturally almost only in animal foods, so plant-based diets rely on fortified foods or supplements.
Pernicious anaemiaAn autoimmune condition that stops the body absorbing B12 properly, and the most common cause of B12 deficiency in the UK.
Gut conditions or surgeryCrohn's disease, coeliac disease or stomach and bowel surgery can reduce how much B12 you absorb.
Certain medicinesLong-term use of some medicines, including metformin and stomach acid-reducing medicines, can lower B12 absorption.
Older ageAbsorption of B12 from food can become less efficient as we get older.
Pregnancy and planning pregnancyB12 needs are higher during pregnancy and breastfeeding, so levels are worth discussing with your midwife or GP.

What a B12 Blood Test Can and Cannot Tell You

A B12 test can help to

  • Measure the level of vitamin B12 in your blood
  • Show whether your B12 level may be low and worth discussing with a GP
  • Give you a starting point if you have symptoms such as tiredness or pins and needles
  • Check how your levels respond to diet changes, supplements or treatment

A B12 test cannot by itself

  • Identify why your B12 is low, for example diet versus an absorption problem
  • Confirm or rule out pernicious anaemia
  • Fully rule out deficiency if symptoms continue despite a normal result
  • Replace medical assessment, examination or further investigation

A standard B12 result is a useful first step, but it is one piece of the picture. Some people have symptoms of deficiency with a result in the expected range, and clinicians sometimes use additional tests such as active B12, folate or a full blood count to look more closely. For balanced information, read the NHS guidance on vitamin B12 or folate deficiency anaemia.

B12, Folate and Anaemia: Choosing the Right Test

B12 and folate work closely together, and a lack of either can cause a type of anaemia where red blood cells are larger than normal. Depending on your symptoms, you may want B12 on its own or as part of a wider check.

TestBest for
Vitamin B12 Blood Test (this test)A focused check of your vitamin B12 level
Vitamin B12 Active (Cobalamin) Blood TestMeasuring active B12 (holotranscobalamin) specifically
Vitamin D, B12 & Folate Levels Blood TestChecking B12 and folate together, plus vitamin D, in one appointment
Folate (Vitamin B9) Blood TestChecking folate on its own
Anaemia Blood TestLooking more widely at possible causes of anaemia
Tired All The Time Blood TestPersistent fatigue where B12 is only one of several possible causes

Choose this vitamin B12 test if B12 is the one result you want. If you are investigating ongoing tiredness, our guide to the best blood tests for fatigue explains which markers are commonly checked together.

Preparing for Your B12 Blood Test

  • Fasting: a standalone B12 test does not usually require fasting. If you are booking other tests at the same appointment, follow the preparation instructions for those tests.
  • Supplements and injections: B12 supplements, multivitamins and B12 injections can raise your result. Let the Swift Blood Tests team know what you take so your result can be read in context.
  • Prescribed treatment: do not stop any prescribed medicine or B12 treatment unless your GP or healthcare professional advises you to.
  • On the day: drink water as normal and wear a top with sleeves that roll up easily.

Always follow the preparation instructions provided with your booking. If you are unsure whether your appointment timing is suitable, contact the Swift Blood Tests team before your visit.

Understanding Your B12 Result

Your result will show your vitamin B12 level alongside the laboratory's reference range. Reference ranges vary between laboratories, so your result should always be read against the range on your own report rather than figures found online.

Low resultMay point to B12 deficiency. Share it with your GP, who can look for the cause and advise on treatment.
Borderline resultMay need repeat testing or additional tests, such as active B12 or folate, especially if you have symptoms.
High resultOften reflects recent supplements or injections. Mention it to your GP if you are not taking B12.

A result within the expected range does not remove the need to seek advice if symptoms continue or get worse.

How to Book Your Private B12 Test

Choose your visit typeSelect Clinic Visit, Home Visit (Essex only) or Kit Only in the booking options at the top of this page.
Check your basketReview the price for your chosen visit type and confirm your booking.
Give your sampleA trained phlebotomist takes a small venous blood sample, or you use your venous collection kit.
Get your resultYour sample is analysed by the laboratory, and you can discuss your result with your GP or healthcare professional.

Find a B12 Blood Test Near You

Looking for a B12 blood test near me or a private B12 test near me? Use the clinic finder to see Swift Blood Tests locations, or choose a home visit if you are in Essex and would rather have your blood taken at home.

Find Your Nearest Clinic

Frequently Asked Questions

What is a B12 blood test?

A B12 blood test checks the level of vitamin B12 in your blood. Vitamin B12 helps your body make healthy red blood cells and supports your nervous system, and the result can be discussed with a GP or healthcare professional.

What does a vitamin B12 test measure?

This test measures vitamin B12, also called cobalamin, in a venous blood sample. It is a focused B12 test rather than a full nutritional or anaemia panel.

What is the difference between a B12 test and an active B12 test?

A standard B12 test measures vitamin B12 in your blood. An active B12 test measures holotranscobalamin, the portion of B12 bound to the protein that delivers it to your cells. Swift offers a separate Vitamin B12 Active (Cobalamin) Blood Test if you want active B12 measured specifically.

What are the symptoms of low B12?

Common symptoms of low B12 include tiredness and low energy, pins and needles, a sore red tongue, mouth ulcers, muscle weakness, memory or concentration problems, low mood and changes in vision. Seek medical advice promptly if you have numbness, balance problems or confusion.

Can a B12 blood test diagnose B12 deficiency?

A B12 blood test can show whether your B12 level is low, which is an important part of checking for deficiency. It cannot show the cause on its own, and some people have symptoms with a result in the expected range, so your result should be discussed with a GP or healthcare professional.

Do I need to fast for a B12 blood test?

A standalone B12 test does not usually require fasting. If you are booking other tests at the same appointment, follow the preparation instructions for those tests, and always follow the instructions provided with your booking.

Should I stop taking B12 supplements before my test?

B12 supplements, multivitamins and injections can raise your result, so let the Swift Blood Tests team know what you take. Do not stop any prescribed medicine or B12 treatment unless your GP or healthcare professional advises you to.

Who should consider a B12 test?

You might consider a B12 test if you have symptoms such as ongoing tiredness or pins and needles, follow a vegan or vegetarian diet, have a gut condition such as Crohn's or coeliac disease, have had stomach surgery, or take medicines such as metformin long term.

Should I test folate as well as B12?

B12 and folate work closely together, and a lack of either can cause a similar type of anaemia, so they are often checked together. Swift's Vitamin D, B12 and Folate Levels Blood Test checks both in one appointment.

Can low B12 cause tiredness?

Yes. Tiredness and low energy are among the most common symptoms of low B12. Fatigue has many possible causes, though, so a wider fatigue blood test may be more useful if B12 is only one of several things you want to check.

How much does a private B12 test cost?

The current price for this test is shown in the booking options at the top of this page. Select your visit type and check your basket total before you pay.

Where can I get a B12 blood test near me?

You can book a clinic visit through the Swift Blood Tests clinic finder, choose a home visit if you are in Essex, or order a venous collection kit. Use the Find Your Nearest Clinic page to see locations.

Book Your B12 Blood Test

Choose Clinic Visit, Home Visit (Essex only) or Kit Only in the booking options above and get a clear picture of your vitamin B12 level.

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Swift Blood Tests nurse visiting a client at home
5.0 ★★★★★ 221 Google reviews

Great service. I’m not the best with needles, however, Jo made me feel comfortable and at ease which made the whole process much more tolerable. 5 stars from me.

Chris C. Google review · ★★★★★
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