CRP is also used to monitor patients after surgery or other invasive procedures to detect the presence of an infection during the recovery period.
While measuring CRP in the blood is not specific enough to diagnose a particular disease, it does serve as a general, non-specific marker for infection and inflammation which can alert medical professionals that further testing and treatment may be necessary.
Because the concentration of CRP increases in severe cases of inflammation, the test is requested when acute inflammation is a risk (such as from an infection after surgery) or suspected based on patient symptoms. It is also requested to help evaluate chronic inflammatory conditions, such as rheumatoid arthritis and lupus (SLE) and is often repeated to determine whether treatment has been effective. This is particularly useful for inflammatory conditions since CRP levels drop as inflammation subsides.
A high or increasing amount of CRP in your blood suggests that you have an acute infection or inflammation but it does not help in identifying its location or the condition causing it. In people with chronic inflammatory conditions, high concentrations of CRP suggest a flare-up or that treatment has not been effective. If the CRP concentration in your blood drops, it means that you are getting better and inflammation is being reduced.
When your results fall below 10 mg/L, you no longer have clinically active inflammation.
CRP concentrations can be elevated in the later stages of pregnancy, with use of birth control pills or in women taking hormone replacement therapy. Higher levels of CRP have also been observed in the obese.
Another test to monitor inflammation is called the erythrocyte sedimentation rate (ESR). Both CRP and ESR are elevated in the presence of inflammation, but the concentration of CRP in the bloodstream rises and falls faster than ESR. CRP levels may therefore fall to normal if you have been treated successfully, such as for a flare-up of arthritis, but your ESR may remain abnormal for a while longer.
This article was last reviewed on 28 May 2012. | This article was last modified on 24 September 2013.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
The modified date indicates that one or more changes were made to the article. Such changes may or may not result from a full review of the article, so the two dates may not always agree.