Introduction: Sepsis is a prevalent condition threatening the emergency department of hospitals with its role in mortality. The present study intended to investigate the diagnostic value of shock index in early recognition and clinical outcomes of sepsis. Methodology: The current cross-sectional study was conducted on patients having severe sepsis and shock septic. To this end, the patients were clinically screened for sepsis symptoms by the means of checking their vital signs upon arrival to triage, basic laboratory tests, serum lactate level, central venous pressure, arterial blood gases, and shock index upon arrival and after 2 hours of fluid therapy (resuscitation). Data were analyzed using SPSS, version 22, software. Results: The results of Chi-square test indicated that there was a statistically significant correlation between the status of shock index upon arrival and after 2 hours of fluid therapy and the status of serum lactate in patients hospitalized in the emergency department with the early recognition of sepsis (P=0.0001). About % 60.7 of patients with SI˃0.7 showed a mortality rate of %78.7 in compared with %21.3 of patients with SI˂0.7 (P=0.0001). Moreover, the 28-day interval outcome caused % 15.7 of patients to die, whereas %83.3 of them were fully recovered from the hospital. Patients with SI˃0.7 had a hyperlactatemia incidence of % 84.4. On the contrary, patients with SI˂0.7 only showed a hyperlactatemia incidence of % 15.6. Conclusion: The shock index can be used as a tool in prioritization of patients and the emergency departments
