What is the difference between CRP and ESR tests?

Both CRP and ESR (erythrocyte sedimentation rate) are markers of inflammation, but they differ in their mechanisms and uses. CRP is a protein produced by the liver in response to acute inflammation, providing a more immediate and sensitive measure. ESR reflects the rate at which red blood cells settle in a test tube, which increases with chronic inflammation. CRP levels rise and fall faster, making it better for monitoring acute conditions or treatment responses. ESR, on the other hand, is often used for tracking chronic conditions like rheumatoid arthritis. Doctors may order both tests together for a more comprehensive assessment of inflammation.