About CRP Blood Tests

CRP, or C-reactive protein, is a substance that increases in the human body when tissue damage occurs. This protein may rise in the body due to inflammation, traumatic injury, infection, cancer, surgery, or immune diseases such as lupus. CRP can be measured by performing diagnostic testing on a blood sample. CRP blood tests are not specific to any one disease or illness, but they are used to establish the presence of infection or illness.

Function

CRP tests are used diagnostically to determine if an infection is present after surgery, to confirm a connective tissue disorder such as lupus or arthritis, or to determine the effectiveness of a treatment.

Preparation

There is no special preparation required by the patient prior to performing a CRP blood test. A normal diet and activity level can be maintained before the test.

Results

The normal level of CRP is between 0 and 1.0 mg/dL. Levels above 1.1 mg/dL indicate that there is some inflammation present in the body.

Considerations

An elevated level of CRP does not indicate a specific disease diagnosis; if an elevated level is measured, additional testing is always needed to determine the cause of the elevation.

Warning

Medications such as cholesterol-lowering drugs, pain medicines and some hormones or steroids may impact the result of a CRP test.

Resources

• More information on the CRP blood test