What is pernicious anaemia?

Pernicious anaemia is not anaemia? We explain all on the most common cause of a vitamin B12 deficiency in the UK.

Despite its name, pernicious anaemia is not the same as anaemia. When you think of anaemia, you may associate it with the condition that commonly comes alongside low iron and feeling dizzy. Pernicious anaemia, however, is a whole different kettle of fish.  

What is the difference between anaemia and pernicious anaemia? 

Anaemia is a condition that arises when there are a low number of red blood cells or if there isn’t enough haemoglobin (an iron-rich protein that gives the blood its red colour and carries oxygen around the body) within the red blood cells. And it’s usually caused by blood loss (though can also be caused by lack of red cell production or high rates of red blood cell destruction).  

Symptoms of anaemia include: 

  • Extreme fatigue 
  • Lethargy  
  • Feeling faint  
  • Breathlessness  
  • Pale skin  

Anaemia can quite often be prevented or corrected through eating a well-balanced diet and ensuring you have enough iron, folate, and vitamin B12 in your diet.  

Pernicious anaemia is instead an autoimmune disease that affects the stomach and its lining - affecting the body’s ability to absorb vitamin B12. In people with pernicious anaemia, the immune system attacks the parietal cells in the stomach that produce a protein called intrinsic factor (which combines with B12 and is necessary for absorption into the body). 

Without enough intrinsic factors, the body cannot absorb vitamin B12 from the diet and cannot produce enough normal red blood cells – which then leads to anaemia.  

The lack of red blood cells brings about similar symptoms associated with anaemia, including: 

  • Fatigue  
  • Breathlessness  
  • Lethargy 

But this specific anaemia caused by a vitamin B12 deficiency may also present other symptoms. 

Symptoms of anaemia caused by vitamin B12 deficiency, include [1]: 

  • Mouth ulcers 
  • Pins and needles 
  • Sore, red tongue 

The cause of pernicious anaemia is unknown. However, it is more common in [2]: 

  • Women aged over 60 
  • People with a family history of the disease 
  • People with other autoimmune conditions 

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How is pernicious anaemia diagnosed and treated? 

It can take a long time to be diagnosed with pernicious anaemia, as the condition can progress slowly, and its symptoms are often confused with other conditions.  

Many people can go for years without a proper diagnosis, with symptoms becoming progressively more debilitating. If left untreated, pernicious anaemia can lead to several health issues including nerve damage, neurological problems such as memory loss and digestive tract problems [3]. 

However, in most cases, you can reverse symptoms and prevent any long-term damage through simple lifestyle changes, prescribed supplements, and sometimes injections.   

If you suspect vitamin B12 deficiency because of symptoms you are experiencing or because you or a family member has an autoimmune condition, then it is important to get tested quickly.  

You can test your B12 levels quickly with a simple at-home blood test, but here at Medichecks we go one step further and offer a Pernicious Anaemia Blood Test.  

This blood test puts all the relevant tests in one complete profile and is designed to test for active vitamin B12 as well as ferritin, to distinguish between anaemia caused by a vitamin B12 deficiency or an iron deficiency.  

Biomarkers include: 

  • A full blood count - to see if anaemia is affecting the production of your red blood cells. 
  • Methylmalonic acid (MMA) - to confirm B12 deficiency and intrinsic factor antibodies to identify whether pernicious anaemia could be caused by an autoimmune condition. 

If you are found to be deficient in vitamin B12 levels, your treatment will differ depending on the cause of your low levels. For example, if you don’t have enough B12 in your diet, then supplements may be recommended.  

However, if you have pernicious anaemia, you are likely to receive prescription B12 injections for life.  

It may feel overwhelming to be diagnosed with pernicious anaemia, but you are not alone. There is plenty of help and support around.  

The pernicious anaemia society has information and resources on how to deal with your diagnosis, and member support groups to help you get in touch with other people going through the same experience.  



  1.  Nhsinform.scot. (2019). Vitamin B12 or folate deficiency anaemia symptoms and treatments. [online] Available at: https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia [Accessed 14 Feb. 2019]. 
  2. nhs.uk. (2019). Causes. [online] Available at: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/causes/ [Accessed 14 Feb. 2019]. 
  3.  Nhlbi.nih.gov. (2019). Pernicious Anemia | National Heart, Lung, and Blood Institute (NHLBI). [online] Available at: https://www.nhlbi.nih.gov/health-topics/pernicious-anemia [Accessed 14 Feb. 2019]. 

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Pernicious Anaemia Blood Test

A thorough blood test including intrinsic factor antibodies and MMA to help diagnose autoimmune gastritis or pernicious anaemia, conditions which affect your body's ability to absorb vitamin B12

  • Results estimated in 17 working days
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Vitamin B12 (Active) Blood Test

Check your level of active vitamin B12 with our home finger-prick blood test

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Advanced Vitamin B12 Blood Test

A comprehensive investigation into vitamin B12 deficiency including a full blood count plus tests for active vitamin B12, folate and ferritin

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