Both CRP and ESR are markers of inflammation. Generally, ESR does not change as rapidly as the CRP, either at the start of inflammation or as it subsides. CRP is also not affected by as many factors as the ESR, making it a better marker of some types of inflammation. However, because the ESR is easily performed and a CRP requires sophisticated laboratory equipment, the ESR remains valuable as an initial test when a patient is suspected of having an inflammatory disease.
Females tend to have a slightly higher ESR, and menstruation and pregnancy can cause temporary elevations.
Drugs such as dextran, methyldopa (Aldomet), oral contraceptives, penicillamine procainamide, theophylline, and vitamin A can increase ESR, while aspirin, steroids, and quinine may decrease it.