quick read

Also known as
When to get tested?
If your doctor thinks you may have some form of inflammation they will often order C-reactive protein along with other tests. By measuring the level of C-reactive protein (CRP) in your blood it is possible to detect inflammation, assess its severity, and monitor the effectiveness of any treatment you may be having. 
Inflammation is part of the immune system’s response to an irritant, such as an injury, burn or infection.  For instance, it is the redness and swelling you can see developing around a wound or the swelling in the bronchial tubes in your lungs that makes you cough when you have bronchitis. Inflammation also occurs if you have some forms of arthritis (joints) or an auto-immune condition such as Crohn’s disease or ulcerative colitis (intestines).
CRP is a protein made by the liver and released into the blood. It is generally not detectable unless there is some degree of inflammation.
 Sample required
A blood sample drawn from a vein in your arm
Test preparation needed
What results can show
CRP levels rise within a few hours of inflammation occurring.  It is often the first evidence of inflammation somewhere in the body. The level of CRP can jump as much as a thousand-fold in response to bacterial infection and its rise in the blood can precede pain, fever, or other signs or symptoms. However, it is non-specific – it cannot show where inflammation is.  Other tests must be used along with an assessment of your symptoms to make a diagnosis.
A high CRP level can provide confirmation that you have a bacterial infection. CRP is also often used to check for the possibility of infection  after surgery.  If you have a chronic inflammatory disease it can suggest a flare-up or that treatment has not been effective. If the CRP level is elevated in the beginning and then drops, it means that the infection or inflammation is subsiding and/or responding to treatment. 
CRP should not be confused with the more sensitive form of the test, high-sensitivity C-reactive protein (hs-CRP). This is used to assess someone’s risk of heart disease. These are two different tests that measure CRP and each test measures a different range of CRP levels in the blood for different purposes: