High CRP levels indicate that inflammation is present somewhere in the body, states MedlinePlus. Potential causes of inflammation include cancer, connective tissue disease, heart attack, infection or lupus. It's normal for women who are taking oral contraceptives or are in the last half of pregnancy to have positive CRP results.
CRP, or C-reactive protein, is produced in the liver. While CRP levels increase when inflammation is present, the CRP test cannot be used to specify the location of the inflammation, according to MedlinePlus. In addition, individuals with low CRP levels may still have inflammation present. Doctors commonly order CRP blood tests to monitor inflammatory medical conditions such as vasculitis, lupus or rheumatoid arthritis. CRP blood tests may also be used to find out if an anti-inflammatory medication is effectively treating a certain condition.
Some doctors order a more sensitive CRP test, called hs-CRP, to determine a patient's risk for developing heart disease, explains MedlinePlus. Patients with hs-CRP levels of less than 1.0 milligram per deciliter are classified as low risk for experiencing cardiovascular disease. An hs-CRP level of 1.0 to 3.0 indicates average risk, and an hs-CRP greater than 3.0 indicates high risk. The exact role CRP plays in heart disease is unknown.