European Journal of Cardiovascular Medicine

Acute appendicitis is a prevalent surgical emergency, with lifetime risk estimates reaching up to 7% in the general population (1). Prompt diagnosis is critical to avoid complications such as perforation, peritonitis, or abscess formation. However, clinical diagnosis remains challenging due to variable presentations and overlapping symptoms with other abdominal conditions (2,3). While imaging modalities such as ultrasonography and computed tomography have improved diagnostic accuracy, their availability and cost may limit use in resource-constrained settings or in urgent clinical scenarios (4,5).

The search for a reliable, accessible, and cost-effective biomarker has led to increased interest in hematological parameters. Among these, the neutrophil-to-lymphocyte ratio (NLR) has garnered attention as an indicator of systemic inflammation (6). Elevated NLR levels have been reported in various infectious and inflammatory diseases, including appendicitis, and may reflect the immune response associated with disease severity (7,8).

Several studies have evaluated the role of NLR in distinguishing acute appendicitis from nonspecific abdominal pain, reporting promising diagnostic performance when used alongside clinical assessment (9,10). Moreover, NLR is easily calculated from routine complete blood count tests, offering the advantage of rapid and inexpensive assessment (11). Despite these advantages, its utility in emergency settings remains underexplored.

This study was designed to evaluate the predictive value of NLR in diagnosing acute appendicitis in patients presenting to the emergency department with suspected appendicitis.

A prospective observational study was conducted over a six-month period in the emergency department of a tertiary care teaching hospital. The study included patients aged 15 to 60 years who presented with clinical signs and symptoms suggestive of acute appendicitis, such as right lower quadrant abdominal pain, nausea, vomiting, fever, and localized tenderness on examination.

Exclusion criteria included patients with known hematological disorders, ongoing antibiotic therapy, chronic inflammatory diseases, immunosuppressive conditions, or those who had received steroids in the previous week, as these could influence leukocyte counts and inflammatory markers.

All enrolled patients underwent a detailed clinical examination, and laboratory investigations including a complete blood count were performed at admission. The neutrophil-to-lymphocyte ratio (NLR) was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count obtained from the CBC.

Based on the final diagnosis confirmed intraoperatively and by histopathological examination, patients were classified into two groups: confirmed appendicitis (Group A) and non-appendicitis (Group B). The NLR values were compared between these groups.

Statistical analysis was carried out using SPSS version 25.0. Continuous variables were expressed as mean ± standard deviation and compared using independent t-tests. Receiver Operating Characteristic (ROC) curve analysis was conducted to determine the diagnostic accuracy of NLR, and the optimal cutoff value was established. A p-value of <0.05 was considered statistically significant.

A total of 150 patients presenting with suspected acute appendicitis were enrolled, out of which 110 patients (73.3%) had appendicitis confirmed by surgical and histopathological findings (Group A), while 40 patients (26.7%) did not have appendicitis (Group B). The demographic distribution showed a mean age of 27.8 ± 9.5 years in Group A and 29.2 ± 8.7 years in Group B, with no statistically significant difference (p = 0.328).

The mean neutrophil-to-lymphocyte ratio (NLR) in Group A was significantly higher (8.54 ± 2.46) compared to Group B (4.12 ± 1.93), with a p-value of <0.001. A Receiver Operating Characteristic (ROC) curve analysis identified an optimal NLR cutoff value of 6.0 for diagnosing acute appendicitis, with a sensitivity of 84.5% and specificity of 75.0%. The Area Under the Curve (AUC) was 0.852, indicating good diagnostic accuracy.

The comparative results between the two groups are summarized in Table 1.

Table 1: Comparison of Clinical and Hematological Parameters Between Confirmed and Non-Appendicitis Groups

As shown in Table 1, the NLR and other inflammatory parameters were significantly elevated in patients with histologically confirmed appendicitis compared to those without appendicitis.

Figure 1: ROC curve for NLR in Diagnosis of acute appendicitis

Here is the ROC curve illustrating the diagnostic accuracy of NLR in detecting acute appendicitis. As shown, the AUC is approximately 0.85, indicating good discriminatory power.

Table 2: Diagnostic Performance of NLR at Cutoff Value 6.0

As depicted in Figure 1 and Table 2, the ROC analysis confirms that an NLR cutoff of 6.0 yields high sensitivity and acceptable specificity, supporting its utility as a rapid diagnostic tool in emergency care.

This study demonstrates that the neutrophil-to-lymphocyte ratio (NLR) is a useful adjunctive marker in diagnosing acute appendicitis in emergency settings. The significantly higher NLR values in patients with histopathologically confirmed appendicitis compared to those without the condition support previous findings that associate systemic inflammation with elevated NLR (1,2).

The mean NLR in our confirmed appendicitis group was 8.54 ± 2.46, closely aligning with earlier studies that reported NLR values between 6 and 10 in similar cohorts (3,4). The use of an NLR cutoff value of 6.0 in our study yielded a sensitivity of 84.5% and specificity of 75.0%, indicating strong predictive potential. These figures are comparable to diagnostic accuracies observed in research by Kahramanca et al. and Ishizuka et al., both of which advocate for NLR as a cost-effective and accessible diagnostic tool (5,6).

One of the advantages of NLR is its derivation from a routine complete blood count, which is readily available in most emergency departments, particularly in low-resource settings. Unlike imaging techniques, which may be unavailable or delayed due to operational constraints, NLR offers immediate and inexpensive guidance (7,8). This is especially beneficial in pediatric and elderly populations, where symptoms may be atypical and imaging findings equivocal (9,10).

Previous investigations have shown that inflammatory markers like C-reactive protein (CRP), white blood cell (WBC) count, and procalcitonin may assist in the diagnostic process, but none have demonstrated consistent reliability when used in isolation (11,12). Our findings suggest that NLR, when combined with clinical evaluation and WBC count, can enhance diagnostic accuracy and reduce the risk of negative appendectomies.

It is worth noting that although NLR has demonstrated good diagnostic performance, it is not disease-specific. Elevated NLR may also occur in other intra-abdominal infections or inflammatory disorders such as diverticulitis, pancreatitis, or pelvic inflammatory disease (13,14,15). Hence, it should not be used as a standalone diagnostic criterion but rather integrated with clinical judgment and, where feasible, imaging studies.

The main limitations of our study include a relatively small sample size and the exclusion of pediatric and geriatric age groups. Additionally, other biomarkers such as CRP and procalcitonin were not used in combined models, which may have further improved diagnostic precision.

Future studies should explore the use of NLR in conjunction with clinical scoring systems like the Alvarado score and radiological findings to establish a comprehensive diagnostic model. Prospective multicentric studies with larger sample sizes are warranted to validate the generalizability of these findings.

The neutrophil-to-lymphocyte ratio (NLR) is a simple, rapid, and cost-effective biomarker that demonstrates good diagnostic accuracy in identifying acute appendicitis. When used alongside clinical assessment, NLR can support timely decision-making in emergency settings and reduce the reliance on imaging, particularly in resource-limited environments.

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