Evaluating Lactate and CRP for Preoperative Risk Stratification in Acute Appendicitis: A Retrospective Study

Abstract

Aim: Distinguishing complicated from uncomplicated appendicitis is important for patient management. Readily available biomarkers such as serum lactate and C-reactive protein (CRP) may contribute to this process, although their diagnostic accuracy remains debated.
Material and Methods: This retrospective study included 156 patients who underwent appendectomy between 2018 and 2024. Patients were grouped as complicated or uncomplicated based on operative and histopathological findings. Preoperative serum lactate and CRP were analyzed using ROC curves, and multivariate logistic regression was performed to identify potential predictors.
Results: Complicated appendicitis (n=60, 38.5%) was associated with higher lactate (median 2.5 vs 1.6 mmol/L, p<0.001) and CRP levels (median 85 vs 32 mg/L, p<0.001). ROC analysis suggested fair to good discriminative ability for lactate (AUC 0.82) and moderate performance for CRP (AUC 0.78). In multivariate analysis, lactate, CRP, and body temperature appeared as independent predictors, although effect sizes were modest.
Conclusions: Preoperative lactate and CRP levels showed an association with complicated appendicitis and may provide supportive information in risk stratification. However, these biomarkers alone are not sufficient for diagnosis and should be interpreted cautiously in conjunction with clinical and imaging findings. Larger, prospective studies are required to validate their role.

Keywords

• Acute appendicitis
• complicated appendicitis
• lactate
• CRP
• biomarker

References

1. 1. Guan L, Liu Z, Pan G, Zhang B, Wu Y, Gan T, et al. The global, regional, and national burden of appendicitis in 204 countries and territories, 1990-2019: a systematic analysis from the Global Burden of Disease Study 2019. BMC Gastroenterol. 2023;23(1):44. doi:10.1186/s12876-023-02678-7.
2. 2. Selvaggi L, Pata F, Pellino G, Podda M, Di Saverio S, De Luca GM, et al. Acute appendicitis and its treatment: a historical overview. Int J Colorectal Dis. 2025;40(1):28. doi:10.1007/s00384-024-04793-7.
3. 3. Moris D, Paulson EK, Pappas TN. Diagnosis and management of acute appendicitis in adults: a review. JAMA. 2021;326(22):2299-311. doi:10.1001/jama.2021.20502.
4. 4. Snyder MJ, Guthrie M, Cagle S. Acute appendicitis: Efficient Diagnosis and Management. Am Fam Physician. 2018;98(1):25-33.
5. 5. Hajibandeh S, Hajibandeh S, Hobbs N, Mansour M. Neutrophil-to-lymphocyte ratio predicts acute appendicitis and distinguishes between complicated and uncomplicated appendicitis: a systematic review and meta-analysis. Am J Surgery. 2020;219(1):154-63. doi:10.1016/j.amjsurg.2019.04.018.
6. 6. Borruel Nacenta S, Ibáñez Sanz L, Sanz Lucas R, Depetris MA, Martínez Chamorro E. Update on acute appendicitis: Typical and untypical findings. Radiologia (Engl Ed). 2023;65(Suppl 1):S81-91. doi:10.1016/j.rxeng.2022.09.010.
7. 7. Sproston NR, Ashworth JJ. Role of C-Reactive Protein at sites of inflammation and infection. Front Immunol. 2018;9:754. doi:10.3389/fimmu.2018.00754.
8. 8. Moon HM, Park BS, Moon DJ. Diagnostic value of C-Reactive Protein in complicated appendicitis. J Korean Soc Coloproctol. 2011;27(3):122-6. doi:10.3393/jksc.2011.27.3.122.

9. 9. Raja MH, Elshaikh E, Williams L, Ahmed MH. The value of CRP in enhancing diagnosis of acute appendicitis. J Curr Surgery. 2017;7(1-2):7-10. doi:10.14740/jcs316w
10. 10. Deulkar P, Singam A, Mudiganti V, Jain A. Lactate monitoring in intensive care: a comprehensive review of its utility and interpretation. Cureus. 2024;16(8):e66356. doi:10.7759/cureus.66356.
11. 11. Veličković J, Palibrk I, Miličić B, Veličković D, Jovanović B, Rakić G, et al. The association of early postoperative lactate levels with morbidity after elective major abdominal surgery. Bosn J Basic Med Sci. 2019;19(1):72-80. doi:10.17305/bjbms.2018.3186.
12. 12. Vaughan-Shaw PG, Rees JR, Bell E, Hamdan M, Platt T. Normal inflammatory markers in appendicitis: evidence from two independent cohort studies. JRSM Short Rep. 2011;2(5):43. doi:10.1258/shorts.2011.010114.
13. 13. Zülfikaroğlu B, Akkurt G, Akın M, İşman FK, Yastı AÇ, Özmen MZ. Role of serum levels of tumour necrosis factor-like weak inducer of apoptosis (TWEAK) in predicting severity of acute appendicitis. Turk J Surg. 2023;39(2):121-7. doi:10.47717/turkjsurg.2023.5747.
14. 14. Jaschinski T, Mosch CG, Eikermann M, Neugebauer EA, Sauerland S. Laparoscopic versus open surgery for suspected appendicitis. Cochrane Database Syst Rev. 2018;11(11):Cd001546. doi:10.1002/14651858.CD001546.pub4.
15. 15. Wang X, Zhang W, Yang X, Shao J, Zhou X, Yuan J. Complicated appendicitis in children: is laparoscopic appendectomy appropriate? a comparative study with the open appendectomy--our experience. J Pediatr Surgery. 2009;44(10):1924-7. doi:10.1016/j.jpedsurg.2009.03.037.
16. 16. Ünal Y, Aydoğdu YF, Tuncal S, Barlas AM, Balık R, Aydın R, et al. Predictive value of the HALP score in differentiating complicated and uncomplicated acute appendicitis. Ulus Travma Acil Cerrahi Derg. 2025;31(7):621-6. doi:10.14744/tjtes.2025.97198.
17. 17. Günay Y, Taşdöven İ, Kozan R, Koca Ş, Çağlar E. Investigation of predictive value of complete blood countin the diagnosis of acute complicated appendicitis. Med Bull Haseki. 2019;57(1):26-31. doi:10.4274/haseki.galenos.2018.4567.
18. 18. Yu X, Wang J, Liang C, Li Z, Lu W, Lv J, et al. Elevated effluent lactate independently predicts the adverse outcomes of peritoneal dialysis associated peritonitis. Scientific Reports. 2025;15(1):24009. doi:10.1038/s41598-025-09876-1.
19. 19. Prado Rodríguez A, Mato Búa R, Mera Mujico L, Arca Suárez J, López Sánchez M, Sampayo Rodríguez L, et al. Postoperative lactate elevation as a marker of underlying acute mesenteric ischemia. Description of two cases. Rev Esp Anestesiol Reanim (Engl Ed). 2021;68(6):361-366. doi:10.1016/j.redare.2020.08.009.
20. 20. Yesilalioglu S, Az A, Sogut O, Ergenc H, Demirel I. Systemic inflammatory markers for distinguishing uncomplicated and complicated acute appendicitis in adult patients. North Clin Istanb. 2023;10(4):507-13. doi:10.14744/nci.2022.79027.
21. 21. Azadnajafabad S, Awan FZ, Ashjaei B, Alimadadi H, Soti Khiabani M. Analysis of incidence and risk factors of complicated acute appendicitis in Children: evidence from a Tertiary Pediatric Center. Int J Pediatr. 2025;2025:1230753. doi:10.1155/ijpe/1230753.
22. 22. Brombacher M, Moolla H, Nair V, Clarke D. The use of C‐Reactive Protein to predict uncomplicated appendicitis and increase uptake of laparoscopy in low resource hospitals—a retrospective cohort study. World J Surgery. 2024;48(6):1515-20. doi:10.1002/wjs.12202.
23. 23. Feier CVI, Motoc A, Muntean C, Vonica RC, Gaborean V, Olariu S, et al. Systemic inflammatory indices and age-dependent severity in acute appendicitis: a retrospective cohort study. Front Immunol. 2025;16:1620459. doi:10.3389/fimmu.2025.1620459.
24. 24. Berhuni MS, Yönder H, Elkan H, Koyuncu MH, Özgül F, Tatlı F, et al. Diagnostic value of systemic immune inflammation index in identifying complicated acute appendicitis cases. Cureus. 2024;16(11):e73046. doi:10.7759/cureus.73046.