(1) initiation: PCT level was >0.25 ug/L;(2) continuation on day 5: >1 ug/L with 7 more days; 0.51–1 ug/L with 5 more days; 0.26–0.5 ug/L with 3 more days;(3) discontinuation: clinical stabilization plus PCT level was <0.25 ug/L;(4) overruled: life threatening infection, including severe co-morbidity, emerging ICU need, hemodynamic or respiratory instability. The gene discussed is CALCA; the disease is infection.