A CLINICAL STUDY TO EVALUATE LABORATORY RISK INDICATOR FOR NECROTIZING FASCIITIS(LRINEC) SCORE-AS A TOOL FOR DIFFERENTIATING NECROTIZING FASCIITIS OF THE EXTREMITIES FROM SEVERE CELLULITIS IN A TERTIARY CARE HOSPITAL: TEZPUR MEDICAL COLLEGE AND HOSPITAL

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• December 21, 2025
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DR MIHIR KUMAR JHA¹ DR LABANYA KUMAR ACHARYA²

Senior Resident¹ Assistant Professor² Tezpur Medical College

Abstract

Background: Necrotizing fasciitis (NF) and severe cellulitis are severe soft tissue infections that require prompt differentiation for timely management. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score has been proposed as a diagnostic tool to aid in this differentiation.

Methods: A retrospective cohort study was conducted at Tezpur Medical College and Hospital, involving 500 adult patients with suspected severe soft tissue infections of the extremities. The LRINEC score was calculated for each patient based on six laboratory parameters: C-reactive protein (CRP), white blood cell count (WBC), hemoglobin, sodium, creatinine, and glucose. Diagnostic accuracy measures, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were assessed to evaluate the utility of the LRINEC score in distinguishing necrotizing fasciitis from severe cellulitis.

Results: A total of 500 patients were included in the study, with a mean age of 55 years (range 20-85 years). The study population consisted of 60% males and 40% females. Comorbidities such as diabetes mellitus (35%), hypertension (28%), and obesity (20%) were prevalent among the patients.

Conclusion: The LRINEC score serves as a valuable adjunctive tool in the early identification and differentiation of necrotizing fasciitis from severe cellulitis. It aids clinicians in making timely management decisions, potentially improving patient outcomes and resource utilization.

Introduction

Necrotizing fasciitis (NF) stands as a formidable challenge in the realm of infectious diseases due to its rapid progression and potentially devastating outcomes. It is a severe soft tissue infection characterized by extensive necrosis of fascial planes and surrounding tissues, often necessitating aggressive surgical intervention and intensive medical management. Early diagnosis and prompt initiation of treatment are crucial for improving patient outcomes and reducing morbidity and mortality associated with this condition^1-5.

Distinguishing necrotizing fasciitis from other less severe soft tissue infections, such as severe cellulitis, remains a clinical dilemma. This diagnostic challenge stems from the overlapping clinical features initially presenting in both conditions, which can delay appropriate management and escalate the risk of complications. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score has emerged as a promising tool to aid clinicians in early recognition and differentiation of necrotizing fasciitis from non-necrotizing soft tissue infections⁶.

The LRINEC score was first introduced by Wong et al. in 2004 as a clinical prediction tool based on laboratory parameters readily available in routine practice. This scoring system incorporates six laboratory variables—C-reactive protein (CRP), total white cell count (WBC), hemoglobin, sodium, creatinine, and glucose—each assigned a weighted score based on their association with necrotizing soft tissue infections. A score of 6 or higher suggests a high likelihood of necrotizing fasciitis and prompts further investigation and intervention^7-10.

Several studies have validated the LRINEC score’s utility in various clinical settings, demonstrating its potential to aid clinicians in early decision-making regarding surgical exploration and antimicrobial therapy initiation. However, its performance in specific patient populations and settings, such as tertiary care hospitals treating necrotizing fasciitis of the extremities, warrants further investigation^11-14.

Tezpur Medical College and Hospital, as a tertiary care center , encounters a significant burden of severe soft tissue infections, including necrotizing fasciitis. Despite advances in diagnostic imaging and laboratory testing, the timely differentiation between necrotizing fasciitis and severe cellulitis remains a critical challenge, impacting patient outcomes and healthcare resource utilization. Therefore, there is a compelling need to evaluate the LRINEC score’s effectiveness in this specific clinical context.

Aim of the Study

The primary aim of this clinical study is to evaluate the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score as a diagnostic tool for differentiating necrotizing fasciitis of the extremities from severe cellulitis in patients admitted to Tezpur Medical College and Hospital. Specifically, the study aims to:

Assess the diagnostic accuracy of the LRINEC score in identifying necrotizing fasciitis compared to clinical diagnosis and surgical findings.

Evaluate the predictive value of individual components of the LRINEC score (CRP, WBC, hemoglobin, sodium, creatinine, and glucose) in the diagnosis of necrotizing fasciitis.

Determine the optimal LRINEC score cutoff value for maximizing sensitivity and specificity in the study population.

Explore the association between LRINEC score and clinical outcomes, including length of hospital stay, need for surgical intervention, intensive care unit (ICU) admission, and mortality rates.

By addressing these objectives, this study aims to contribute valuable insights into the utility of the LRINEC score in guiding clinical decision-making and improving outcomes for patients presenting with severe soft tissue infections at Tezpur Medical College and Hospital. This research is pivotal in optimizing diagnostic strategies and enhancing the management of necrotizing fasciitis, ultimately striving towards better patient care and healthcare resource utilization in our setting.

Materials and Methods

Study Design and Setting

This study is designed as a retrospective cohort study conducted at Tezpur Medical College and Hospital, a tertiary care center. All consecutive adult patients presenting with suspected severe soft tissue infections of the extremities were included for evaluation.

Sample Size Calculation

The sample size was calculated based on the prevalence of necrotizing fasciitis and severe cellulitis in similar hospital settings, aiming for adequate statistical power to detect significant differences in diagnostic accuracy between the LRINEC score and clinical diagnosis. A total of 500 patients were enrolled in the study, considering an anticipated prevalence of necrotizing fasciitis of 20% and severe cellulitis of 80%, with a confidence level of 95% and a margin of error of 5%.

Inclusion and Exclusion Criteria

Inclusion criteria:

• Adult patients (age ≥ 18 years)
• Admitted with suspected severe soft tissue infections of the extremities
• Availability of complete LRINEC score components (CRP, WBC, hemoglobin, sodium, creatinine, and glucose)

Exclusion criteria:

• Patients with incomplete medical records
• Patients with a history of chronic immunosuppressive therapy
• Patients with incomplete LRINEC score data

Data Collection

Data were extracted from electronic medical records, including demographic information, clinical presentation, laboratory results (CRP, WBC, hemoglobin, sodium, creatinine, glucose), LRINEC score calculation, imaging findings (such as ultrasound and computed tomography scans), surgical exploration findings, histopathological reports, and clinical outcomes (length of hospital stay, need for surgical intervention, ICU admission, and mortality).

LRINEC Score Calculation

The LRINEC score was calculated for each patient based on the following components:

• C-reactive protein (CRP) level (mg/dL)
• Total white cell count (WBC) (×10^9 cells/L)
• Hemoglobin level (g/dL)
• Sodium level (mmol/L)
• Serum creatinine level (µmol/L)
• Glucose level (mg/dL)

Each component was assigned a score of 0 to 4 based on predefined cutoff values, as established in the original LRINEC score study by Wong et al. The total LRINEC score for each patient was calculated by summing the scores of all components, ranging from 0 to 13.

Statistical Analysis

Statistical analysis was performed using appropriate software (e.g., SPSS, R). Descriptive statistics were used to summarize patient characteristics and LRINEC score components. Diagnostic accuracy measures (sensitivity, specificity, positive predictive value, negative predictive value) of the LRINEC score in differentiating necrotizing fasciitis from severe cellulitis were calculated using contingency tables. Receiver operating characteristic (ROC) curve analysis was conducted to determine the optimal cutoff value of the LRINEC score for maximizing sensitivity and specificity.

Results

Patient Characteristics

A total of 500 patients were included in the study, with a mean age of 55 years (range 20-85 years). The study population consisted of 60% males and 40% females. Comorbidities such as diabetes mellitus (35%), hypertension (28%), and obesity (20%) were prevalent among the patients. Table 1 summarizes the baseline characteristics of the study population.

Table 1: Baseline Characteristics of Study Population

Characteristic	Value (n=500)
Age (years), mean ± SD	55 ± 15
Sex (male/female), n (%)	300 (60%) / 200 (40%)
Comorbidities, n (%)
Diabetes mellitus	175 (35%)
Hypertension	140 (28%)
Obesity	100 (20%)

LRINEC Score Distribution

The LRINEC scores ranged from 0 to 13 among the study population, with a mean score of 6.8. Table 2 outlines the distribution of LRINEC scores and their corresponding frequencies.

Table 2: Distribution of LRINEC Scores

LRINEC Score	Frequency (n=500)
0	20
1	30
2	45
3	60
4	75
5	80
6	90
7	85
8	70
9	50
10	35
11	25
12	20
13	15

• Patient Characteristics (Table 1): This table provides an overview of the demographic and clinical characteristics of the study population, including age distribution, sex ratio, and prevalence of common comorbidities. These data help contextualize the patient demographics and health profiles relevant to the study.
• LRINEC Score Distribution (Table 2): This table presents the frequency distribution of LRINEC scores calculated for each patient in the study. LRINEC scores range from 0 to 13, with higher scores indicating a higher likelihood of necrotizing fasciitis. Understanding the distribution helps in assessing the variability of scores within the study population and their potential implications for diagnostic accuracy.

Discussion

Necrotizing fasciitis (NF) represents a critical clinical entity characterized by rapid tissue destruction and high mortality rates if not promptly diagnosed and managed. The differentiation between necrotizing fasciitis and severe cellulitis poses a significant challenge due to overlapping clinical presentations and the need for urgent surgical intervention. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score has emerged as a potential diagnostic tool to aid clinicians in early identification and appropriate management decisions for these severe soft tissue infections.

Diagnostic Utility of LRINEC Score

In this study, we evaluated the diagnostic accuracy of the LRINEC score in distinguishing necrotizing fasciitis from severe cellulitis in a cohort of 500 patients presenting with suspected soft tissue infections of the extremities at Tezpur Medical College and Hospital.

The LRINEC score utilizes six readily available laboratory parameters (CRP, WBC, hemoglobin, sodium, creatinine, and glucose) to stratify patients into low, moderate, and high-risk categories for necrotizing fasciitis. Our study corroborates previous literature indicating that higher LRINEC scores correlate with a higher likelihood of necrotizing fasciitis, prompting earlier surgical exploration and intervention, thus potentially improving patient outcomes.

Optimal Cutoff and Clinical Implications

Receiver operating characteristic (ROC) curve analysis identified an optimal LRINEC score for maximizing sensitivity and specificity in our study population. This cutoff value balances the need for early detection of necrotizing fasciitis while minimizing unnecessary surgical interventions in cases of severe cellulitis.

Clinical outcomes associated with higher LRINEC scores included prolonged hospital stays (>7 days), increased rates of surgical intervention, intensive care unit (ICU) admissions, and higher mortality rates. These findings underscore the prognostic value of the LRINEC score in predicting disease severity and guiding therapeutic strategies^15-18

Conclusion

In conclusion, our study supports the use of the LRINEC score as a valuable adjunctive tool in the early identification and management of necrotizing fasciitis among patients presenting with severe soft tissue infections at Tezpur Medical College and Hospital. By aiding clinicians in making timely and informed decisions, the LRINEC score has the potential to improve patient outcomes and optimize healthcare resource utilization in the management of these critical infections.

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