Diagnostic Utility of Serum Sodium Compared With C-reactive Protein and Total Leukocyte Count for Predicting Appendiceal Perforation and Clinical Outcomes in Adult Patients With Acute Appendicitis: A Prospective Observational Study.

Background Early identification of complicated appendicitis remains a clinical challenge despite advances in diagnostic methods. Appendiceal perforation is associated with increased morbidity, prolonged hospitalization, and adverse postoperative outcomes. Conventional inflammatory markers such as C-reactive protein (CRP) and total leukocyte count (TLC) have shown variable utility in predicting disease severity. Recently, serum sodium has emerged as a potential biomarker for identifying complicated appendicitis. The present study evaluated the utility of serum sodium as a predictor of appendiceal perforation and compared its performance with CRP and TLC. Methods This prospective observational study was conducted in the Department of General Surgery at Maharishi Markandeshwar Medical College and Hospital, Solan, Himachal Pradesh, India. A total of 72 adult patients with acute appendicitis diagnosed using combined clinical, laboratory, imaging, intraoperative, and histopathological findings were enrolled. Serum sodium, CRP, TLC, and other laboratory parameters were measured at admission before surgical intervention. Cases were categorized as non-perforated and perforated appendicitis. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis, and correlations with hospital stay and postoperative complications were assessed. Results The mean age of participants was 41.1±15.26 years, and males constituted 68.1% of the cohort. Perforated appendicitis was identified in 15.3% of patients and was associated with higher age (49.55±18.30 vs. 39.59±14.31 years) and lower serum sodium levels (133.63±3.80 vs. 137.92±2.88 mEq/L) compared with non-perforated appendicitis. Hyponatremia showed a strong association with perforation. ROC analysis demonstrated good discriminatory ability of serum sodium (area under the curve or AUC=0.803), with a sensitivity of 63.6% and a specificity of 91.8% at a cutoff value of 135 mEq/L, indicating high specificity but modest sensitivity for predicting perforated appendicitis. CRP showed the best overall diagnostic accuracy (AUC=0.807), whereas TLC demonstrated limited predictive utility (AUC=0.626). Patients with perforated appendicitis had longer hospital stay (5.0±2.14 vs. 3.44±1.09 days) and higher postoperative complication rates (45.5% vs. 3.3%) compared to those with non-perforated appendicitis. Serum sodium showed a negative correlation with hospital stay (r=-0.261) and also demonstrated predictive ability for postoperative complications (AUC=0.733). Conclusions Serum sodium is a readily available and cost-effective adjunctive biomarker associated with appendiceal perforation and post-operative complications in patients with acute appendicitis. Although CRP demonstrated superior overall diagnostic accuracy, serum sodium may serve as a useful adjunctive biomarker in risk stratification of acute appendicitis. Incorporation of serum sodium into multimodal risk assessment strategies may facilitate earlier recognition of complicated disease; however, larger multicenter studies are required before routine clinical implementation can be recommended.