This large retrospective cohort study has identified four easily measurable clinical variables: serum albumin level ≤ 24.5 g/L, CRP level >228 mg/L and a combination of WCC >12 × 103 mcL and respiratory rate >17 resps/min (as this proved more discriminatory than either value alone) that if measured within or around 48 hours of CDI diagnosis, are capable of predicting the risk of mortality in patients with CDI. The gene discussed is CRP; the disease is clostridium difficile infection.