Procalcitonin behaves as a fast responding acute phase protein in vivo and in vitro.

Objectives: Procalcitonin (PCT) is a 13 kD protein of which plasma concentrations are strongly increased in inflammatory states. PCT concentrations are claimed to have a more powerful discriminatory value for bacterial infection than the acute phase proteins serum amyloid A (SAA) or C-reactive protein (CRP). The source of production and its mechanism of induction are unknown.