C-reactive protein (CRP) by nephelometry (plasma)

Why Is This Test Done?

Your healthcare provider may order CRP testing to check for signs of inflammation. This could be due to infections (like pneumonia or urinary tract infections), autoimmune conditions (such as rheumatoid arthritis), or other health concerns where inflammation plays a role. It may also be used to monitor treatment progress or detect early signs of problems.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast before the test if it involves drawing blood, but CRP plasma tests often don’t require fasting. Avoid strenuous activity or certain medications (like nonsteroidal anti-inflammatory drugs) for a few days before testing, as they can affect results.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The blood will be sent to a lab where it is analyzed using nephelometry, a method that measures how much CRP is present in your plasma.

What Are the Possible Results?

Results are typically reported in milligrams per liter (mg/L). Higher CRP levels may indicate inflammation, while lower levels suggest minimal or no inflammation. Your results will be interpreted by your doctor based on your overall health and medical history.