Procalcitonin and C-Reactive Protein as Diagnostic Biomarkers for Bacterial Gastroenteritis: A Retrospective Analysis

Background/Aim: Bacterial and viral gastroenteritis present with overlapping symptoms, including vomiting, diarrhea, and abdominal pain. Stool tests have been used to differentiate between them; however, stool cultures are time-consuming and stool polymerase chain reaction (PCR) tests are expensive. The role of the clinical value of procalcitonin (PCT) and C-reactive protein (CRP) as diagnostic markers of bacterial gastroenteritis remains to be investigated. This study evaluated the diagnostic value of PCT for the early diagnosis of bacterial gastroenteritis. Methods: The medical records of patients diagnosed with gastroenteritis by the emergency department with positive stool PCR results confirming the diagnosis between 1 January 2020 and 31 July 2024 were retrospectively reviewed. Demographic characteristics and laboratory findings, including PCT and CRP levels, were analyzed. The area under the curve (AUC) for the diagnosis of bacterial gastroenteritis was assessed to determine the diagnostic potential of PCT and CRP. Results: Among the 1882 cases identified, 1435 met the inclusion criteria. CRP exhibited a sensitivity of 79.0% and specificity of 78.6% (AUC: 0.848, 95% CI: 0.815–0.881) in diagnosing bacterial gastroenteritis. In comparison, PCT showed lower sensitivity (60.3%) and specificity (62.6%) (AUC: 0.660, 95% CI: 0.614–0.706). However, in patients aged >17 years with fever (≥38 °C), PCT demonstrated an improved AUC of 0.767 (95% CI: 0.603–0.932; p = 0.019). Conclusions: CRP demonstrated moderate sensitivity in predicting bacterial gastroenteritis; however, its false-negative rate suggests limitations in clinical decision-making. While PCT may assist clinicians in identifying bacterial gastroenteritis in febrile adult patients, its diagnostic accuracy remains suboptimal, necessitating further validation through larger studies.