Acute phase reactant.

• To check for severity of inflammatory disease and effectiveness of anti-inflammatory treatment.
• To help diagnose rheumatoid arthritis, which is characterized by high levels of CRP.
• Used for early detection of postoperative infection.

Blood test detects blood levels of C-reactive protein, or CRP, which appears in the blood during inflammatory diseases.

None.

Blood is drawn from a vein and analyzed for CRP. Several methods may be used for the analysis, including radioimmunoassay and agglutination.

Follow procedure for drawing blood.

Pregnancy may increase CRP levels.

CRP levels higher than 8 micrograms per milliliter may indicate presence of infection or inflammation.

• There's no risk.
• It may be more sensitive than the sedimentation rate in detecting early- and late-stage infection.

• It detects inflammation but not its cause (cannot be used to confirm a specific diagnosis).
• It's more complicated and expensive than sedimentation rate.

• If levels are elevated and arthritis is suspected, a rheumatoid factor test may be done. In other conditions, the test confirms the presence of systemic inflammation, and therapy may be started.
• If levels are normal, the test indicates lack of systemic inflammation, and no further tests are necessary.