Role of Serum C-Reactive Protein in Improving the Diagnostic Accuracy of the Modified Alvarado Score in Patients with Suspected Acute Appendicitis: A Cross-sectional Study
Anjuman Ara *
Department of Orthopedic Surgery, Rajshahi Medical college, Rajshahi, Bangladesh.
Mahedi Afroz Shakil
Department of Surgery, Gonoshasthaya Samaj Vittik Medical College, Savar, Dhaka, Bangladesh.
Fahim Foysal Kollol
Department of Surgery, Mymensingh Medical College, Mymensingh, Bangladesh.
Md. Jahangir Alam
Department of Pediatric Surgery, Gonoshasthya Samaj Vittik Medical College, Savar, Dhaka, Bangladesh.
Noorjahan Akter
Department of Surgery, Dhaka Medical College, Dhaka, Bangladesh.
Zaki Ibne Bari
Department of Surgery, Community Based Medical College Bangladesh, Mymensingh, Bangladesh.
Tamanna Rahman Shanta
Department of Surgery, Patuakhali Medical College Hospital, Patuakhali, Bangladesh.
Raisul Islam
Department of General Surgery, Shaheed Monsur Ali Medical College, Dhaka, Bangladesh.
Sharmin Akter Rime
Department of Pediatric Surgery, International Medical College, Gazipur, Bangladesh.
Pinjay Biswas
Department of Surgery, Sher-e-Bangla Medical College and Hospital, Barisal, Bangladesh.
Afroja Tuhin
Department of Cancer Cell and Molecular Biology, University of Leicester, Leicester, United Kingdom.
*Author to whom correspondence should be addressed.
Abstract
Background: Acute appendicitis is a common surgical emergency; delayed diagnosis may increase morbidity, whereas diagnostic uncertainty may lead to unnecessary appendectomy. The Modified Alvarado Score (MAS) is widely used, but its performance may be limited in equivocal cases. Serum C-reactive protein (CRP) may provide complementary inflammatory information.
Objective: To assess whether serum CRP improves the diagnostic performance of MAS in patients with suspected acute appendicitis, using histopathological findings as the reference standard.
Methods: This hospital-based cross-sectional study included 223 consecutive patients aged ≥13 years who underwent appendectomy at Mymensingh Medical College Hospital, Bangladesh, from January 2022 to June 2023. MAS and qualitative serum CRP (>6 mg/L) were assessed preoperatively. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy were calculated for MAS, CRP, and the combined criterion of MAS ≥7 with raised CRP.
Results: Histopathological examination confirmed acute appendicitis in 209 patients (93.7%). MAS showed 84.69% sensitivity, 78.57% specificity, and 84.30% diagnostic accuracy. CRP showed 93.78% sensitivity, 64.29% specificity, and 91.93% diagnostic accuracy. The combined criterion showed 83.73% sensitivity, 85.71% specificity, 98.87% PPV, 26.09% NPV, and 83.86% diagnostic accuracy. Thus, CRP alone had the highest sensitivity and accuracy, whereas the combined criterion had the highest specificity and PPV.
Conclusion: Serum CRP provides useful adjunctive information to MAS. A positive MAS-CRP combination may strengthen diagnostic confidence because of its high specificity and PPV; however, neither a low MAS nor a normal CRP result reliably excludes acute appendicitis.
Keywords: Acute appendicitis, modified alvarado score, C-reactive protein, diagnostic accuracy, sensitivity, specificity, histopathology, appendectomy, clinical scoring