Skip to content

Half price clinic visit with any blood test!

Home > Vitamin B12 (Active) Blood Test
Vitamin B12 (Active) Blood Test

Vitamin B12 (Active) Blood Test


A simple finger-prick blood test to measure levels of active vitamin B12 which is essential for healthy nerves, blood cells and DNA.
Blood sample 1 biomarker included Results in 4 working days from sample receipt at lab
Vitamin B12 (Active) Blood Test
Vitamin B12 (Active) Blood Test
Vitamin B12 (Active) Blood Test
Vitamin B12 (Active) Blood Test
Vitamin B12 (Active) Blood Test

Is it for you?

Do you have symptoms of weakness, fatigue, brain fog and pins and needles? Do you have a condition like an underactive thyroid, Crohn's or coeliac disease which might affect your ability to absorb vitamin B12? Do you avoid animal based foods which raises your risk of B12 deficiency? Perhaps you are taking a supplement and just want to check your levels. If so, this easy and affordable test is right for you.

What's included?

Biomarker profile

  • Vitamins

Vitamins (1 Biomarker)

Special instructions

Do not take vitamin B12 for two weeks prior to this test. If your B12 is prescribed ask your doctor whether you should stop before testing. Do not take biotin supplements for 2 days prior to this test. If you are taking prescribed biotin you should discuss this with your doctor.

From the expert

Vitamin B12 is an essential water-soluble vitamin that is found in virtually all meat products and certain algae such as seaweed. It helps maintain healthy nerve cells and red blood cells and is also needed to make DNA, the genetic material in all cells.

Around 70% of the vitamin B12 in your blood is inactive which means that it isn't available for your body to use. This test measures levels of the biologically-active component of vitamin B12, thought to be the best early indicator of vitamin B12 deficiency. Vitamin B12 deficiency symptoms usually develop gradually but can worsen if the condition goes untreated. Symptoms of vitamin B12 deficiency include fatigue and weakness, headaches, feeling faint, pale skin, palpitations and pins and needles. As vitamin B12 is necessary for the formation of healthy red blood cells, a deficiency can cause red blood cells to become enlarged (macrocytic) which affects their ability to transport oxygen around the body. 

Vitamin B12 is bound to the protein in food and is released by the acid in the stomach during digestion. Once released, it combines with a substance called intrinsic factor before it is absorbed into the bloodstream. Pernicious Anaemia (an autoimmune condition) prevents absorption by stopping the production of intrinsic factor and is the leading cause of Vitamin B12 deficiency.

The human body stores several years' worth of vitamin B12, however, people with pernicious anaemia, vegetarians, vegans as well as people who have recently had gastric bypass surgery are all at a greater risk of deficiency. Even if you get enough vitamin B12 in your diet, if your body doesn't absorb it properly then you can become deficient in vitamin B12. People who may have absorption problems include the elderly, people with low stomach acid (including those taking PPI's) people who drink excessive alcohol, and people with inflammatory bowel conditions like Crohn's or Coeliac disease.

Why take this test?

  • You simply want to check you are getting enough vitamin B12 in your diet
  • you are experiencing symptoms which you think might be related to vitamin B12 deficiency
  • You are vegetarian or vegan and want to check your vitamin B12 level
  • You have Crohn's or coeliac disease and want to check you are absorbing vitamin B12
Laboratories you can trust

Laboratories you can trust

Trusted by the NHS and private clinics alike, you can be sure of the highest testing standards from our UKAS accredited partner laboratories.

Dr Sam Rodgers - Chief Medical Officer

Expert interpretation of your results

One of our team of doctors will review your results and give you personalised advice based on your medical history, lifestyle and health and fitness goals.

Your personal health centre

Your personal health centre

Discover the easy way to track your health through our online portal, View your results with doctor's advice, monitor any changes over time and see the improvements you can make to your health with simple lifestyle changes.

Questions? Let us help
Questions? Let us help

Questions? Let us help

Our customer care team is on-hand to help you find the test that's right for you. Get in touch via phone, live chat or email.

What our customers say

We ask every Medichecks customer about their experience - read what they have to say


Our tests are not a substitute for seeing your doctor, especially if you are suffering symptoms. Our doctors will interpret your results based on the information you have provided, but will not diagnose, consult or provide any treatment. You will be advised to see your doctor for any necessary follow-up action.