C-reactive protein (CRP) by nephelometry

Why Is This Test Done?

Your healthcare provider may order a CRP test to check for signs of inflammation, monitor conditions like arthritis, heart disease, or infections, or evaluate responses to treatments. It can also help assess risk for certain diseases or conditions, such as cardiovascular disease.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your blood is drawn from a vein, but this is not always required. If you’re taking blood from a fingerstick (e.g., for a finger-prick test), fasting may not be necessary.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm or, if needed, from a finger. The blood sample is then sent to a lab where it is analyzed using nephelometry, a method that measures how much light scatters from CRP particles in your serum.

What Do the Results Mean?

Results are reported in milligrams per liter (mg/L). Higher levels may indicate inflammation, infection, or other health issues, while lower levels suggest minimal inflammation. Your results will be interpreted by your healthcare provider based on your overall health and medical history.