The Confusing State of Sepsis Definition


  • There is large variability in incidence and clinical outcome (including mortality) in sepsis patients based on the definition used.
  • The differing definitions make it difficult for providers and health systems to:
    • Evaluate outcomes such as Time-Zero, mortality and length of stay
    • Implement quality improvement initiatives
    • Compare results between sites using different locations
    • Identify patients who meet clinical criteria but fail to meet regulatory criteria or vice versa
  • The various approaches lead to much confusion.


  • The lack of a “gold standard” definition to sepsis has resulted in a confusing state of multiple, rapidly changing clinical and regulatory possibilities.
  • Although the SEP-1 requirements have been amended twice, they retain the SEPSIS-2 2001 definition of 2 or more SIRS criteria coupled with the 2012 treatment recommendations from the Surviving Sepsis Campaign.
  • The result is a complex solution involving:
    a. Difficult to implement hospital sepsis quality improvement initiatives and
    compare sites using different definitions.
    b. Hospitals supporting a robust data abstraction service to support SEP-1.
    c. Private insurance payers denying payment when documentation does not cite SEPSIS-3 2016 criteria.
    d. Some patients will meet both SEPSIS-2 and SEPSIS-3 definitions
    e. Other patients will meet only 1 of the definitions and get fully paid but fail
    CMS SEP-1 criteria or vice versa


A recent retrospective analysis from Barnes Jewish Hospital/Washington University in St Louis, MO used hospital electronic medical record and administrative claims data to compare 5 different sepsis definitions. (Yu SC, Betthauser KD, Gupta A, et al. Critical Care Medicine 2021;49(4):e433-e443)

Six years of data were reviewed (2012-2017) which included 286,759 inpatient encounters.

Table 1: Sepsis Definitions

Table 2: Results of Differing Definitions

  • Number of sepsis cases varies based on the definition used
    • No singular definition captures the entire spectrum
    • Only 4,370 cases met the criteria for all the definitions
  • Time to onset varied as Time-Zero (T-0) definitions vary across the definitions.
    • CMS SEP-1 had the longest time to onset due to the Time-Zero (T-0) definition used.
    • T-0 for CMS SEP-1 is defined as the time the last point of the criteria is met.
  • The CDC ASE had the highest mortality and length of stay, with one of the lowest incidence rates.
  • A number of these definitions included sepsis and septic shock patients together
    • Therefore, the true incidence of sepsis within this set cannot be determined.

Table 3: Mortality Based on Definitions


  • Varying sepsis definitions lead to confusion.


    Hospitals and providers who target to meet CMS SEP-1 requirements, maybe denied payments by insurers based on more clinically oriented definitions (SEPSIS-3 or CDC ASE).


  • Hospitals and providers who target to meet CMS SEP-1 requirements, maybe denied payments by insurers based on more clinically oriented definitions (SEPSIS-3 or CDC ASE).
  • A more consistent list of criteria for sepsis definition is required.

Erkan Hassan is the Co-Founder & Chief Clinical Officer of Sepsis Program Optimization where he designs & oversees the implementation of solutions to optimize sepsis programs.

To discuss your organization’s Barriers of Effective Sepsis Care, contact Erkan by phone (844) 4SEPSIS (844-473-7747), email (, or video chat.