CRP

C-reactive protein (CRP)

C-reactive protein (CRP) is a protein generated by the liver when inflammation occurs. It acts as an acute phase reactant, which means it helps the immune system by binding to and marking harmful pathogens for destruction. CRP levels begin to rise within 6 hours of an inflammatory trigger and can increase up to 1,000 times their normal levels. 

Measuring CRP in the blood is a straightforward way to assess acute inflammation. Because CRP has a short plasma half-life of 19 hours, its levels decrease quickly once the cause of inflammation is resolved. Monitoring CRP levels over time can be helpful in tracking the progression or improvement of inflammatory conditions.

However, certain diseases, such as systemic lupus erythematosus (SLE), systemic sclerosis, ulcerative colitis, and leukemia, often show only slight increases in CRP levels, even when there is clear evidence of active inflammation. Despite this, a significant rise in CRP can still occur if an infection develops alongside these conditions, which is a critical consideration for patient management.