Acute Phase Reactants

Acute phase response is the sum of the systemic and metabolic changes occurred by release of acute phase proteins in response to inflammatory stimulus. The most important ones of these acute phase reactants are erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen and ferritin. The most widely used ones are ESR and CRP while fibrinogen and ferritin are rarely used and other acute phase reactants have no place in routine clinical use. Although ESR is clinically the most commonly used test, it is fairly nonspecific. Even though CRP is more specific than ESR, because of the high cost of the analysis it has clinically limited usage.