For Research Use Only.  Not for use in diagnostic procedures

C3 is central to the classical, alternative and lectin pathways of complement activation.

The synthesis of C3 is tissue‐specific and is modulated in response to a variety of stimulatory agents. During complement activation, C3 is proteolytically cleaved resulting in release of the anaphylatoxic peptide C3a.

C3a is a small polypeptide consisting of 74 amino acids. C3a itself is very short‐lived and in serum cleaved rapidly into the more stable C3a‐desArg (also called acylation stimulating protein, ASP). Therefore, measurement of C3a‐desArg allows reliable conclusions about the level of complement activation in the samples.