Different studies have highlighted the role of PCT as a diagnostic marker for bacterial infection, which is often more effective than other common markers used in clinical practice, such as CRP, ESR, and WBC, and may be more reliable than some experimental markers such as interleukin-6 (IL-6) or interleukin-8 (IL-8) [4]. The gene discussed is CXCL8; the disease is bacterial infectious disease.