Abstract
Background
The Adult Sepsis Event (ASE) criteria, developed by the US. Centers for Disease Control and Prevention (CDC), utilize electronic Sequential Organ Failure Assessment (eSOFA) scores derived from structured electronic health records to retrospectively detect organ dysfunction in patients with suspected sepsis. While validated primarily in inpatient cohorts, their applicability in emergency department (ED) populations remains uncertain. Moreover, the impact of including isolated serum lactate elevation as a marker of organ dysfunction in eSOFA has not been systematically evaluated.
Methods
We retrospectively reviewed data from 698 patients (aged ≥ 19 years) with suspected infections presenting to the EDs of three institutions from September 1 to 30, 2023. Blood cultures were obtained from all patients. Patients were classified according to Sepsis-3 (≥ 2-point SOFA score increase from baseline) and ASE-defined eSOFA (organ dysfunction occurring within ± 2 days of blood culture collection). Extended eSOFA additionally included isolated lactate elevation (≥ 2.0 mmol/L). Diagnostic performance was assessed using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).
Results
Among 698 patients, 456 (65.3%) met Sepsis-3 criteria, 251 (35.9%) met ASE-defined eSOFA, and 340 (48.7%) met extended eSOFA criteria. Mortality was highest (19.8%) among patients classified by both SOFA and eSOFA. ASE-defined eSOFA demonstrated moderate sensitivity (52.0%) and high specificity (94.2%), with a PPV of 94.4%. Extended eSOFA improved sensitivity (64.3%) but lowered specificity (80.6%). Mortality increased with the number of dysfunctional organ categories. Notably, the inclusion of isolated lactate elevations identified additional high-risk patients not captured by eSOFA.
Conclusion
ASE-defined eSOFA moderately aligns with Sepsis-3 criteria, effectively identifying high-risk ED sepsis cases. Extended eSOFA criteria with lactate enhance sensitivity but reduce specificity, suggesting tailored application based on clinical settings and available resources.
Supplementary Information
The online version contains supplementary material available at 10.1186/s40560-025-00815-w.
Keywords: Sepsis, Surveillance, Adult sepsis event, Lactate, Sequential organ failure assessment score
Background
Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection, posing significant global health challenges due to high morbidity and mortality rates [1–5]. Initially defined in 1991 by the Systemic Inflammatory Response Syndrome (SIRS) criteria, sepsis was redefined in 2016 as the third international consensus definitions (Sepsis-3), employing the Sequential Organ Failure Assessment (SOFA) score to determine organ dysfunction. Although Sepsis-3 defines a clinically relevant definition of sepsis utilizing the SOFA score, its application often demands comprehensive laboratory testing and baseline assessments, complicating practical implementation [6–8].
The Adult Sepsis Event (ASE), developed by the CDC primarily for surveillance and epidemiological tracking, utilizes structured data directly extracted from electronic health records (EHRs) to identify clinically significant organ dysfunction with greater stringency [9]. The ASE definition includes the electronic Sequential Organ Failure Assessment (eSOFA), a streamlined set of criteria for identifying acute organ dysfunction directly from electronic health records. Most previous studies evaluating eSOFA have focused on hospitalized cohorts, leaving its applicability in emergency department (ED) settings relatively unexplored [10, 11]. Given its standardized, EHR-based structure, we applied the ASE criteria retrospectively to ED patients with suspected infection to evaluate their concordance with the Sepsis-3 definition and to explore their utility in retrospective surveillance and institutional comparisons across acute care settings.
Serum lactate, an established marker of sepsis severity and prognosis, is frequently employed in clinical practice. However, within eSOFA, lactate elevations (≥ 2.0 mmol/L) are optional due to variability in institutional testing practices, potentially limiting comprehensive case identification [12–14]. While some institutions have immediate access to lactate testing, others—particularly in resource-limited settings—may lack such capacity. Therefore, it is important to evaluate whether including isolated lactate elevation improves the performance of eSOFA-based criteria without compromising their applicability across diverse clinical environments.
Therefore, this multicenter study aims to evaluate the performance of eSOFA criteria, both with and without the inclusion of isolated serum lactate elevation (≥ 2.0 mmol/L), in identifying sepsis among ED patients compared to the established Sepsis-3 (SOFA) criteria. We hypothesized that eSOFA’s stricter criteria would yield a higher positive predictive value (PPV) for identifying severe cases, whereas Sepsis-3 criteria would capture a broader patient population.
Methods
Study design and data sources
This retrospective multicenter study was conducted in three hospitals in South Korea: Inje University Sanggye Paik Hospital (a secondary university-affiliated hospital in Seoul), Sejong Chungnam National University Hospital (a regional general hospital in Sejong), and Samsung Medical Center (a tertiary referral hospital in Seoul). All sites operate 24-h emergency departments and represent a range of institutional types and patient volumes.
Patients were eligible for inclusion if they underwent blood culture testing at ED presentation during September 2023, based on the clinical judgment of the treating physician who suspected infection. Patients were excluded if they lacked data required to calculate the SOFA score. The final study population included 698 patients. We included only patients who were admitted, transferred, or died in the ED; no patients discharged home were part of the study population. (Supplementary Fig. 1).
The primary objective was to compare the identification of sepsis using the Sepsis-3 criteria (≥ 2-point increase from the baseline Sequential Organ Failure Assessment (SOFA) score) and the Adult Sepsis Event (ASE)-based eSOFA definition, which identifies organ dysfunction occurring within ± 2 days of blood culture collection.
Sepsis‐3 definition
The Sepsis-3 definition requires suspected or confirmed infection in conjunction with an acute increase in the SOFA score by 2 or more points from baseline, indicating new organ dysfunction [15]. In the absence of prior clinical or laboratory data, the baseline SOFA score was assumed to be zero. For the respiratory SOFA component, we also utilized SaO2/FiO2 ratios using previously validated conversion criteria when PaO2/FiO2 values were unavailable [16]. Patients with incomplete or missing clinical or laboratory data necessary for SOFA calculation were excluded from the analysis.
Adult sepsis event (eSOFA) definition
The ASE framework identifies sepsis based on three core components: (1) the collection of blood cultures, (2) initiation of sustained antibiotic therapy for at least four consecutive days (or until in-hospital death or discharge), and (3) the presence of acute organ dysfunction within a ± 2-day window surrounding the date of blood culture collection [14]. Organ dysfunction was defined by the occurrence of at least one of the following criteria: (1) new vasopressor initiation (norepinephrine, dopamine, epinephrine, phenylephrine, or vasopressin), provided that none of these agents were administered on the preceding calendar day; (2) a new episode of invasive mechanical ventilation occurring at least one full calendar day after discontinuation of any previous ventilatory support; (3) renal dysfunction, evidenced by a doubling of serum creatinine or a ≥ 50% reduction in estimated glomerular filtration rate (eGFR) from baseline; (4) hepatic dysfunction, defined as a total bilirubin level ≥ 2.0 mg/dL with a ≥ 100% increase from baseline; (5) coagulopathy, documented by a platelet count < 100,000 cells/μL along with a ≥ 50% reduction from the baseline platelet count; and (6) an optional indicator of elevated serum lactate (≥ 2.0 mmol/L), which may be included at the investigator’s discretion for enhanced detection of sepsis when lactate monitoring is performed consistently. In this study, we included adult ED patients with suspected infection, as indicated by blood culture collection and initiation of a minimum 4-day antibiotic regimen, who met at least one of the above eSOFA organ dysfunction criteria, including serum lactate elevation. To account for the optional nature of lactate in the eSOFA criteria, we additionally identified and analyzed a subgroup of patients with isolated serum lactate ≥ 2.0 mmol/L in the absence of other organ dysfunction, referred to as the extended eSOFA (Ext-eSOFA) group. The most abnormal (worst) value within ± 2 days of blood culture collection was used for each variable, following the ASE framework, regardless of ED stay.
Statistical analysis
The diagnostic performance of the eSOFA definition in identifying patients who met Sepsis-3 (SOFA-based) criteria was evaluated using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), derived from a standard 2 × 2 contingency table. Sensitivity was defined as the proportion of SOFA-positive patients correctly identified by eSOFA, while specificity represented the proportion of SOFA-negative patients accurately classified as such. PPV was calculated as the proportion of eSOFA-positive cases that were also SOFA-positive, and NPV as the proportion of eSOFA-negative cases that were SOFA-negative. Continuous variables were summarized as median and interquartile range (IQR), and categorical variables as number and percentage. All statistical analyses were performed using Python (version 3.10), with descriptive diagnostic metrics calculated from 2 × 2 contingency tables.
Results
Patient distribution and characteristics
During the 1-month study period, a total of 10,660 adult patients visited the emergency departments of the three participating hospitals. Among them, 744 underwent blood culture testing based on clinical suspicion of infection, and 698 patients were included in the final analysis after excluding those with missing SOFA data. Baseline characteristics were largely comparable across three groups: those who fulfilled Sepsis-3 criteria (SOFA score ≥ 2, n = 456), those who met ASE-defined eSOFA criteria (n = 251), and those classified under the extended eSOFA definition including isolated lactate elevation ≥ 2.0 mmol/L without other organ dysfunction (n = 340), as detailed in Table 1.
Table 1.
Patient characteristics
| Category | Variable | SOFA (N = 456) N (%), Median [IQR] | eSOFA (N = 251) N (%), Median[IQR] | Extended eSOFA (N = 340) N (%), Median[IQR] | Total (N = 698) N (%), Median[IQR] |
|---|---|---|---|---|---|
| Baseline | Age | 72 (61–81) | 72 (61–80) | 71 (61–80) | 69 (58–79) |
| Sex (M) | 278 (60.9%) | 151 (60.1%) | 215 (63.2%) | 393 (56.3%) | |
| BMI | 22.6 (19.9–24.8) | 22.6 (20.4–24.9) | 22.1 (20.0–24.8) | 22.3 (19.7–24.8) | |
| Comorbidities | Cardiovascular diseases (CVDs) | 56 (12.3%) | 34 (13.5%) | 43 (12.6%) | 80 (11.5%) |
| Chronic neurological disorders | 62 (13.6%) | 41 (16.3%) | 49 (14.4%) | 85 (12.2%) | |
| Chronic respiratory diseases | 107 (23.5%) | 59 (23.5%) | 84 (24.7%) | 156 (22.3%) | |
| Connective tissue diseases | 15 (3.3%) | 8 (3.2%) | 13 (3.8%) | 27 (3.9%) | |
| Chronic liver diseases | 120 (26.3%) | 74 (29.4%) | 92 (27.0%) | 156 (22.3%) | |
| Diabetes mellitus | 101 (22.1%) | 61 (24.3%) | 82 (24.1%) | 127 (18.2%) | |
| Chronic kidney disease (CKD) | 48 (10.5%) | 29 (11.5%) | 32 (9.4%) | 58 (8.3%) | |
| Hematologic malignancies | 39 (8.6%) | 23 (9.2%) | 28 (8.2%) | 49 (7.0%) | |
| Solid tumors | 158 (34.6%) | 95 (37.8%) | 131 (38.5%) | 222 (31.8%) | |
| Immunocompromised state | 70 (15.4%) | 39 (15.5%) | 57 (16.8%) | 104 (14.9%) | |
| Site of infection | Pulmonary | 153 (33.6%) | 79 (31.5%) | 128 (37.6%) | 234 (33.5%) |
| Abdominal | 148 (32.5%) | 84 (33.5%) | 105 (30.9%) | 225 (32.2%) | |
| Urinary | 80 (17.5%) | 45 (17.9%) | 56 (16.5%) | 112 (16.0%) | |
| Skin/soft tissue | 18 (3.9%) | 7 (2.8%) | 9 (2.6%) | 47 (6.7%) | |
| Catheter-related | 4 (0.9%) | 3 (1.2%) | 3 (0.9%) | 5 (0.7%) | |
| Neurologic | 2 (0.4%) | 1 (0.4%) | 2 (0.6%) | 5 (0.7%) | |
| Without clear primary site of infection | 53 (11.7%) | 34 (13.5%) | 39 (11.5%) | 71 (10.2%) | |
| Admission | General ward | 341 (74.8%) | 174 (69.3%) | 241 (70.9%) | 560 (80.2%) |
| ICU | 82 (17.9%) | 67 (26.7%) | 76 (22.4%) | 88 (12.6%) | |
| Outcome | Death | 60 (13.1%) | 49 (19.5%) | 59 (17.4%) | 68 (9.7%) |
SOFA Sequential Organ Failure Assessment; eSOFA electronic Sequential Organ Failure Assessment; SD standard deviation; BMI body mass index; CVDs cardiovascular diseases; CKD chronic kidney disease; ICU intensive care unit
There were no statistically significant differences among these groups in terms of median age (75.0 ± 16.8 vs. 72.0 ± 14.0 vs. 69.0 ± 14.3 years, respectively), sex distribution, body mass index (BMI), or the prevalence of major comorbidities including cardiovascular, neurologic, and respiratory diseases, diabetes mellitus, chronic liver or kidney disease, connective tissue disorders, hematologic malignancies, solid tumors, and immunocompromised states. Similarly, the distribution of infection sites (pulmonary, abdominal, urinary tract, skin and soft tissue, catheter-related, and central nervous system) did not differ significantly between groups. Patients without microbiological confirmation were included based on strong clinical suspicion of infection, and 208 patients (29.8%) had microbiologically confirmed infections. Overall, the mean age was 70.0 ± 15.9 years, and 393 patients (56.3%) were male. The most common comorbidities included solid tumors (31.8%), chronic respiratory disease (22.3%), and diabetes mellitus (18.2%). Pulmonary (33.5%) and abdominal (32.2%) infections were the most frequent infection sites.
Disposition and outcomes
Among patients classified by SOFA (n = 456), 17.9% (n = 82) were admitted to the intensive care unit (ICU), 74.8% (n = 341) to general wards, and in-hospital mortality was 13.1%. In the eSOFA group (n = 251), ICU admission occurred in 26.7% (n = 67), general ward admission in 69.3% (n = 174), and mortality reached 19.5%. The extended eSOFA group (n = 340) showed intermediate outcomes, with ICU admission in 22.4% (n = 76), general ward admission in 70.9% (n = 241), and mortality of 17.4%. Across the entire cohort (N = 698), ICU admission was 12.6%, general ward admission was 80.2%, and overall mortality was 9.7%.
Comparison between eSOFA and SOFA criteria with and without lactate inclusion
Among the 698 patients, 456 (65.3%) met SOFA (score ≥ 2) criteria and 251 (35.9%) met eSOFA criteria. There was an overlap of 237 patients (33.9%) who met both criteria. Notably, 14 patients (2.0%) met only the eSOFA criteria, while 219 (31.4%) met only the SOFA criteria. The remaining 228 patients (32.7%) did not fulfill either set of criteria.
When patients with isolated serum lactate elevation (≥ 2.0 mmol/L) were included under the extended eSOFA definition, the total number of eSOFA-positive patients increased to 340 (48.7%). Under this extended eSOFA definition, 293 patients (41.9%) met both SOFA and extended eSOFA criteria. The number of patients meeting only extended eSOFA criteria increased to 47 (6.7%), while those meeting only SOFA criteria decreased to 163 (23.4%). Consequently, the number of patients not meeting either criterion declined to 195 (27.9%) (Fig. 1).
Fig. 1.
Overlap of patients classified as septic by Sepsis-3 (SOFA), ASE-defined eSOFA, and extended eSOFA criteria. a Distribution of patients classified as sepsis-positive according to Sepsis-3 SOFA score (≥ 2) and the ASE-defined eSOFA criteria. b Patient classification using extended eSOFA criteria that include isolated lactate elevation (≥ 2.0 mmol/L). This extension increased overlap with SOFA and reduced the proportion of SOFA-only or dual-negative cases. SOFA Sequential Organ Failure Assessment; eSOFA electronic Sequential Organ Failure Assessment; Ext-eSOFA extended eSOFA including isolated lactate elevation; ASE Adult Sepsis Event
The distribution of organ dysfunction differed notably between sepsis definitions (Fig. 2). Among patients meeting sepsis definition by SOFA criteria, those with individual organ SOFA scores ≥ 2 were classified as having organ dysfunction for comparison. Compared to SOFA, eSOFA showed reduced detection of pulmonary dysfunction (39 vs. 81 patients) and failed to identify patients with neurologic dysfunction (0 vs. 51 patients). The difference between eSOFA and extended eSOFA was primarily attributable to the inclusion of 89 additional patients with isolated lactate elevation (≥ 2.0 mmol/L).
Fig. 2.
Distribution of Organ Dysfunction and Increased Lactate (≥ 2.0 mmol/L) Among Patients Identified by SOFA, eSOFA, and Extended eSOFA criteria. Number of patients with specific organ dysfunctions identified by SOFA with individual organ scores ≥ 2 (gray), eSOFA (black), and extended eSOFA with isolated lactate elevation (Ext-eSOFA, striped bars). eSOFA showed reduced pulmonary dysfunction detection and missed neurologic dysfunction compared to SOFA. Ext-eSOFA enhanced detection, especially for lactate-associated dysfunction. SOFA Sequential Organ Failure Assessment; eSOFA, electronic Sequential Organ Failure Assessment; Ext-eSOFA extended eSOFA including isolated lactate elevation
Diagnostic performance of eSOFA criteria
Figure 3 presents the 2 × 2 contingency tables comparing eSOFA and extended eSOFA classifications with the Sepsis-3 definition. The standard eSOFA criteria (excluding isolated lactate elevation) demonstrated a sensitivity of 52.0%, specificity of 94.2%, positive predictive value (PPV) of 94.4%, and negative predictive value (NPV) of 51.1%. The extended eSOFA definition (including lactate ≥ 2.0 mmol/L) increased sensitivity to 64.3% and NPV to 58.8%, but decreased specificity to 80.6% and PPV to 86.2%.
Fig. 3.
Diagnostic Agreement and Discriminative Performance of eSOFA and Extended eSOFA Criteria Compared with Sepsis-3. a 2 × 2 contingency table and diagnostic performance of the eSOFA definition excluding isolated serum lactate elevation, showing improved specificity and positive predictive value compared to the extended version. b 2 × 2 contingency table and diagnostic performance of the extended eSOFA definition, which includes isolated serum lactate elevation (≥ 2.0 mmol/L) as an additional criterion. eSOFA electronic Sequential Organ Failure Assessment; PPV positive predictive value; NPV negative predictive value
Prevalence and mortality according to diagnostic classification
A total of 456 patients (65.3%) met SOFA criteria, with an in-hospital mortality of 13.3%. The eSOFA criteria identified 251 patients (35.9%) with a higher mortality rate of 19.5%. In comparison, the extended eSOFA criteria captured 340 patients (48.7%) and showed an intermediate mortality of 17.4% (Fig. 4).
Fig. 4.
Prevalence and in-hospital mortality among patients classified with sepsis according to SOFA, eSOFA, and extended eSOFA criteria. The extended eSOFA incorporates isolated serum lactate elevation (≥ 2.0 mmol/L) as an additional criterion for defining sepsis. SOFA Sequential Organ Failure Assessment; eSOFA electronic Sequential Organ Failure Assessment; Ext-eSOFA, extended eSOFA including isolated lactate elevation
Subgroup analysis (Supplementary Fig. 2) demonstrated that patients fulfilling both SOFA and eSOFA criteria had the highest mortality at 19.8%, representing 33.9% of the cohort. Those meeting only SOFA or only eSOFA criteria had lower mortality rates of 5.9% and 14.3%, respectively. Patients who did not meet either criterion (n = 228) had the lowest mortality at 2.6%. When applying the extended eSOFA definition, the subgroup meeting both SOFA and extended eSOFA criteria remained the highest-risk group, with a mortality of 19.1%. Other subgroups identified under the extended definition showed varied mortality ranging from 2.5% to 6.4%, depending on overlap with SOFA classification.
Mortality according to number of organ dysfunction categories
Mortality increased in proportion to the number or severity of organ dysfunctions across all classification systems (Fig. 5). In the SOFA-based classification, mortality rose from 7.8% in patients with scores of 2–3 to 55.6% in those with scores > 11. Among patients classified by eSOFA, mortality progressively increased with the number of dysfunctional organ categories: 10.2% for one, 20.8% for two, 27.5% for three, 35.0% for four, 26.7% for five, and 100% for six. A similar stepwise trend was also observed in the extended eSOFA group, including patients with isolated lactate elevation.
Fig. 5.
Distribution and in-hospital mortality by SOFA score, eSOFA components, and extended eSOFA (Ext-eSOFA) criteria. a Proportion of patients and corresponding in-hospital mortality by SOFA score categories. b Distribution and mortality by the number of eSOFA organ dysfunction criteria met. c Distribution and mortality by the number of extended eSOFA (Ext-eSOFA) criteria, with patients meeting only the lactate criterion (≥ 2.0 mmol/L) shown separately. SOFA Sequential Organ Failure Assessment, eSOFA Electronic Sequential Organ Failure Assessment, Ext-eSOFA Extended eSOFA including isolated lactate elevation
Discussion
This multicenter study demonstrates two main strengths regarding the diagnostic utility of the Adult Sepsis Event (ASE)-defined eSOFA criteria in emergency department (ED) settings. First, our research represents the first multicenter evaluation to assess the applicability and feasibility of eSOFA criteria among ED patients, addressing a significant gap identified in previous studies predominantly conducted among hospitalized patients. Second, the study systematically examines the impact of incorporating isolated serum lactate elevation into the eSOFA definition, providing empirical guidance on its inclusion tailored to institutional contexts and resources [17, 18].
Unlike previous studies focusing primarily on hospitalized cohorts [10, 11, 19], our findings confirm that eSOFA criteria effectively identify ED patients with severe organ dysfunction, who subsequently experience higher mortality. By validating the application of eSOFA criteria across multiple emergency settings, this research underscores the feasibility and potential utility of eSOFA as a reliable surveillance method in community-based epidemiological monitoring [14]. Thus, our study supports broader use of eSOFA criteria beyond its original inpatient-based framework.
Additionally, this study evaluates the diagnostic implications of including isolated serum lactate elevation within the eSOFA framework. While lactate measurement has been considered optional in previous institutional practices [14], our results illustrate that integrating lactate measurement substantially enhances sensitivity, allowing the identification of additional patients who otherwise might be missed. In addition, lactate levels can be influenced by various noninfectious and comorbid factors, their interpretation must be context-specific and adapted to institutional practices [18, 20–22]. Therefore, our analysis highlights that this extended definition reduces specificity and positive predictive value (PPV), emphasizing the need for context-specific decisions based on institutional capabilities, priorities, and clinical workflows.
In this study, we compared the diagnostic performance of Sepsis-3 criteria with the eSOFA and extended eSOFA definitions. Specifically, eSOFA exhibited moderate sensitivity (51.9%) but high specificity (94.2%) and PPV (94.4%), while the extended eSOFA with lactate improved sensitivity (64.3%) but reduced specificity (80.6%) and PPV (86.2%). Similar trends were reported previously, with eSOFA criteria having lower sensitivity (50.8%) compared to Sepsis-3 but a high PPV (82.9%), indicating the selection of a more severely ill patient group due to stricter criteria used by eSOFA [10]. Another study has reported higher sensitivity (91.6%) and specificity (98.3%) for eSOFA but notably lower PPV (57.4%), suggesting variability in clinical practice and case definitions across different populations [11]. These discrepancies may relate to the characteristics of our emergency department cohort, which likely differed from hospitalized populations in previous reports. In addition, the structure of the eSOFA criteria, which identifies pulmonary dysfunction only in the presence of mechanical ventilation and does not include neurologic dysfunction criteria, may have contributed to its lower sensitivity by missing cases with non-ventilated respiratory failure or altered mental status. Given that the ASE criteria were originally developed by the CDC for surveillance purposes rather than clinical diagnosis, our study did not aim to evaluate their utility as real-time decision-making tools. Instead, we assessed their applicability in emergency department settings for retrospective identification of sepsis cases. The eSOFA-based definitions demonstrated high specificity and positive predictive value, suggesting potential utility in sepsis surveillance and institutional comparisons across acute care settings.
When interpreting the mortality patterns observed in this study, it is important to consider the original intent and structure of each diagnostic framework. Because of its stringent criteria of eSOFA, sensitivity remains lower compared to Sepsis-3, potentially excluding patients with milder or early-stage organ dysfunction, consistent with prior findings [4, 9]. Furthermore, unlike Sepsis‐3, which relies on SOFA scoring to facilitate mortality prediction, eSOFA was primarily designed as a surveillance tool and does not inherently incorporate prognostic features [4, 23]. In these data, mortality under Sepsis-3 criteria rose progressively with higher SOFA scores. In contrast, the eSOFA-based classification did not exhibit a uniform pattern of increasing mortality with each additional organ failure. This variability in the eSOFA group may be attributable to the small number of cases available for analysis, limiting the ability to draw definitive conclusions from these results. Including patients with elevated lactate alone in the eSOFA definition may help capture less severe cases of sepsis and partially address the limitations; however, such modifications should be carefully adapted based on institutional context and resource availability.
Despite these strengths, several limitations of this study must be acknowledged. A potential source of misclassification is that eSOFA can capture organ dysfunction not strictly attributable to infection; in our series, approximately 10% of cases initially had no clearly identified source, yet were ultimately deemed infectious based on clinical judgment, thereby mitigating—but not eliminating—the possibility of misclassification. In addition, because the study included only patients who had blood cultures drawn, some individuals who met Sepsis-3 criteria but did not undergo culture may have been excluded, which could affect the interpretation of our findings. Taken together, these observations reinforce the importance of interpreting eSOFA findings within the appropriate clinical context, especially when differentiating noninfectious from infectious causes of organ dysfunction.
Conclusions
In this multicenter study of adult patients presenting to the ED with suspected infection, the eSOFA criteria showed moderate concordance with the SOFA criteria. Although eSOFA identified a smaller subset of patients, these patients demonstrated higher mortality, suggesting that eSOFA preferentially captures individuals with more advanced organ dysfunction. Including isolated serum lactate elevation (≥ 2.0 mmol/L) enhanced diagnostic sensitivity but reduced specificity and PPV, highlighting an inherent trade-off that must be balanced according to institutional priorities and resource availability. Overall, eSOFA presents a feasible and scalable diagnostic adjunct for identifying high-risk sepsis patients, especially in time-constrained or resource-limited clinical settings. Its adaptability to EHR systems, coupled with its selective identification of severe cases, supports its implementation as both a surveillance and triage tool in diverse healthcare environments.
Supplementary Information
Acknowledgements
Not applicable.
Author contributions
H.P. and R.E.K. contributed equally to the conception and design of the study, data collection and analysis, interpretation of results, and drafting of the manuscript. H.S.O. contributed to data collection, analysis, and manuscript review. J.Y.M. participated in study design, data interpretation, and critical review of the manuscript. Y.C. and G.Y.S. supervised the study, contributed to study conception and design, data interpretation, and critical revision of the manuscript for important intellectual content. All authors read and approved the final manuscript.
Funding
Not applicable.
Data availability
The data supporting the findings of this study were extracted from the electronic health records of three tertiary hospitals in Korea. Due to patient privacy and institutional policies, the raw data are not publicly available. However, de-identified data and analysis code may be made available by the corresponding author upon reasonable request and with appropriate institutional approval.
Declarations
Ethics approval and consent to participate
Due to the retrospective nature of this study and the use of de-identified patient data from electronic medical records, the requirement for informed consent was waived by the Institutional Review Boards in accordance with local regulations.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Hyojun Park and Ryoung-Eun Ko have contributed equally to this work as first authors.
Change history
8/24/2025
The affiliations have been corrected.
Contributor Information
Youjin Chang, Email: yjchang0110@gmail.com.
Gee Young Suh, Email: smccritcare@gmail.com.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The data supporting the findings of this study were extracted from the electronic health records of three tertiary hospitals in Korea. Due to patient privacy and institutional policies, the raw data are not publicly available. However, de-identified data and analysis code may be made available by the corresponding author upon reasonable request and with appropriate institutional approval.