The purpose of a C-reactive protein test is to measure the amount of a particular type of protein in a person's blood, which indicates levels of inflammation in the body, according to WebMD. This C-reactive protein, or CRP, is found in high levels as a result of some types of diseases or infections.
Commonly, a CRP test may be done following surgery to check for infection, states WebMD. Additionally, a CRP test may be performed to check for or to find and monitor conditions such as cancer of the lymph nodes, lupus, rheumatoid arthritis, inflammatory bowel disease or an infection in a person's bone. However, a CRP test simply shows that inflammation is present. This test does not show the cause of inflammation.
The reference range for a normal CRP level is less than one milligram per deciliter or less than 10 milligrams per liter, according to WebMD. A high-sensitivity C-reactive protein test yields different results. This type of test is used to measure a person's risk of heart problems. Normal results are less than 0.1 milligrams per deciliter or less than 1 milligram per liter. Some conditions can affect the results of a CRP test, such as having an infection, being overweight, pregnancy, the use of an intrauterine device and exercise.