Understanding CRP (C-Reactive Protein)

The level of CRP in your blood can determine how likely you are to develop hypertension, heart disease and other conditions. It can be hard to understand how it works, so we've gone back to basics.  

Your blood is packed full of different cells, gases and other molecules that help keep your body working. Some of these substances act as biomarkers – they can be used to detect problems in different areas of the body. They are released as a response to inflammation or infection. Biomarkers don't cause disease themselves, but they can be used to predict how likely a disease is to occur in the future.

C-Reactive Protein (CRP) is an important biomarker that's strongly associated with heart health. It's produced in the liver and released when a part of the body becomes inflamed. People with arthritis, inflammatory bowel disease and some autoimmune disorders are likely to have higher levels of CRP in their blood. CRP is also released during infection and after an injury to a muscle, including the heart1.

A high-sensitivity CRP test can be used to predict a person's risk of developing heart disease. The level of CRP in your blood should be as low as possible, ideally under 1mg per litre of blood. This normal level depends on your age, gender, lifestyle and other factors.

A high reading may indicate that you have an infection or that part of your body has inflammation. Most blood tests routinely include a test for abnormally high levels of CRP2.

Having a CRP level of between 1mg and 3 mg increases your risk of developing future heart disease by over a quarter. A reading between 3mg and 10mg pushes this risk even higher, increasing the risk by 60%4. It's important to find the cause of a high CRP level, so it can be investigated and treated as quickly as possible.

There are a range of at-home CRP test kits on the market. These generally use a finger-prick blood test to estimate your CRP levels, oftenwithin minutes. More expensive and reliable tests require blood to be sent to a lab for testing. Home tests are relatively inexpensive, quick and easy, but they are not a substitute for visiting your GP.

  • https://www.southtees.nhs.uk/services/pathology/tests/crp/
    1. https://labtestsonline.org.uk/tests/c-reactive-protein (NHS-approved site)
    2. https://www.ncbi.nlm.nih.gov/books/NBK441843/
    3. https://pubmed.ncbi.nlm.nih.gov/19805771/