Predictive value of immature granulocyte count and C-reactive protein for complicated acute appendicitis

INTRODUCTION: Preoperative identification of complicated acute appendicitis is important for surgical planning and perioperative management. This study assessed the associations of preoperative immature granulocyte count (IG#), immature granulocyte percentage (IG%), and C-reactive protein (CRP) with complicated appendicitis and their ability to discriminate complicated from uncomplicated disease.
METHODS: This retrospective cohort study included 100 adults who underwent appendectomy for acute appendicitis between January and December 2025. Patients were classified as having complicated appendicitis (n=22) or uncomplicated appendicitis (n=78) according to operative and histopathological findings. Group comparisons, receiver operating characteristic (ROC) curve analyses, and a parsimonious multivariable logistic regression model including IG#, CRP, age, and sex were performed.
RESULTS: CRP [58.6 (19.3–155.6) vs. 27.0 (5.3–66.3) mg/L; p = 0.048] and IG# [0.07 (0.06–0.09) vs. 0.06 (0.04–0.08) ×10³/µL; p = 0.039] were higher in complicated appendicitis, whereas IG% did not differ significantly (p = 0.209). The areas under the curve were 0.644 (95% confidence interval [CI]: 0.510–0.779) for IG#, 0.639 (95% CI: 0.505–0.773) for CRP, and 0.587 (95% CI: 0.445–0.729) for IG%. After adjustment, CRP remained independently associated with complicated appendicitis (odds ratio [OR]: 1.122 per 10 mg/L increase; 95% CI: 1.038–1.213; p = 0.004), whereas IG# did not (OR: 1.024 per 0.01 ×10³/µL increase; 95% CI: 0.970–1.081; p = 0.389).
DISCUSSION AND CONCLUSION: Among the evaluated biomarkers, only CRP remained independently associated with complicated appendicitis after adjustment. IG# and CRP showed limited discriminatory performance and may be more suitable for clinical risk stratification alongside clinical and imaging findings than for definitive diagnosis in isolation.

Keywords: acute appendicitis, complicated appendicitis, immature granulocyte count, C-reactive protein, biomarkers