PCT is the precursor to calcitonin, the hormone that manages calcium regulation in the body and has previously been used to simply identify the presence of bacterial infections. Yankov and Bocheva note that along with the traditionally studied values of inflammation such as elevated white blood cell counts and C-reactive protein (CRP), PCT was elevated in their retrospective study of men with active purulent odontogenic infections [11]. The gene discussed is CRP; the disease is bacterial infectious disease.