C-reactive protein (CRP) by nephelometry

What CRP Measures

CRP is produced by the liver in response to inflammation. Elevated levels may indicate conditions such as infections (like pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis), or other inflammatory processes in the body. It’s also sometimes used to monitor healing after surgery or injury.

Why It’s Ordered

Your healthcare provider may order CRP testing if you have symptoms of inflammation, such as fever, joint pain, or unexplained fatigue. It can also help assess risk for certain conditions, like heart disease, or monitor treatment progress for chronic illnesses.

Sample Collection and Preparation

A blood sample is taken from a vein, usually in your arm. The blood is processed to separate serum or plasma for testing. CRP levels are measured using a specialized lab technique called nephelometry, which detects the protein’s presence in the sample.

What to Expect Before Testing

No special preparation is usually needed, but you may be asked to avoid certain medications (like nonsteroidal anti-inflammatory drugs) that could affect inflammation markers. If you’re on blood thinners, let your provider know before the test.