Accuracy of Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) for Diagnosis of Acute Appendicitis Taking Histopathology as Confirmatory

Abstract

Objective: This study was aimed to determine the diagnostic accuracy of ESR and CRP for diagnosis of acute appendicitis, taking histopathology as the gold standard.

Methodology: This cross-sectional study was conducted, at the department of general surgery, Pakistan Institute of Medical Sciences, Islamabad, from September 2024 to March 2025. Patients of either gender, aged 14 to 40 years, presenting within 48 hours onset of right lower quadrant pain, nausea, anorexia, or vomiting, and undergoing appendectomy with Alvarado score >4 were included. Venous blood samples were analyzed for CRP (>0.6 mg/L considered raised) and ESR (>20 mm/h considered raised). Histopathological confirmation of appendicitis served as the reference standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were analyzed.

Results: Overall mean age of the patients was 25.97±6.44 years, with male predominance (62.6%). Histopathological evaluation confirmed acute appendicitis in 91.6% cases, along with erythematous type being most frequent (76.8%). Majority of the patients had raised ESR levels (62.1%), and among these, the majority was histopathology-positive (58.4%), whereas considerable proportion with normal ESR was still histopathology-positive (33.2%), whereas the raised CRP levels even more common (79.5%), with the vast majority of these cases confirmed positive on histopathology (76.8%), seemed more closely aligned with confirmed appendicitis than elevated ESR, with overall sensitivity of 83.91%, specificity of 68.75%, PPV (96.69%), NPV 28.21% and diagnostic accuracy around 82.63%.

Conclusion: CRP is a more accurate and reliable biomarker than ESR for diagnosing acute appendicitis, supporting its routine use to improve diagnostic confidence and reduce unnecessary appendectomies.