A blood CRP, or C-reactive protein, level is measured to determine if inflammation is present in the body, according to MedlinePlus. A positive CRP is usually abnormal and indicates an inflammatory process, such as cancer, infection or heart attack. A positive CRP is normal during the last half of pregnancy.
Doctors commonly order CRP levels to check the status of inflammatory conditions, such as lupus, vasculitis or rheumatoid arthritis, notes MedlinePlus. A CRP level can also tell doctors if anti-inflammatory medication is effectively reducing a patient's inflammation. Sometimes a more sensitive test, called hs-CRP, is utilized to predict a patient's overall risk for heart disease.