C reactive protein (CRP) is a ring-shaped, pentameric protein found in blood plasma, whose circulating concentrations rise in response to inflammation. It is synthesised by the liver in response to factors released by macrophages and fat cells. It plays an important role in innate immunity as an early defense system against infections. Anti-Human CRP is used in the development of immunoassays such as ELISA to study the CRP levels in the plasma sample.