Clinical efficacy of combined detection of serum procalcitonin and C-reactive protein in early differential diagnosis of bacterial and viral pneumonia and analysis of related inflammatory response mechanisms.

BACKGROUND: Early distinction of bacterial etiology from viral causes represents a cornerstone for rational antimicrobial therapy. Through evaluation of dual-biomarker strategies, this investigation examined the diagnostic utility of simultaneous PCT and CRP measurement while elucidating underlying inflammatory pathways. METHODS: A retrospective analysis encompassed 284 patients diagnosed with pneumonia (bacterial: n = 162, viral: n = 122) hospitalized during January 2023 through December 2024. Laboratory parameters including PCT, CRP, leukocyte counts, neutrophil proportions, IL-6, and TNF-α underwent comprehensive measurement. Diagnostic accuracy was evaluated through ROC analysis, with severity correlations systematically assessed. RESULTS: Marked increases in inflammatory markers characterized the bacterial cohort (all parameters p < 0.001). Among single biomarkers, PCT demonstrated superior diagnostic capability (AUC = 0.892). When combined measurement was employed, PCT+CRP yielded optimal performance (AUC = 0.943, sensitivity 92.6%, specificity 89.3%). Positive correlations emerged between biomarker concentrations and clinical severity scores (PCT: r = 0.782, CRP: r = 0.743, both p < 0.001). Following multivariate adjustment, concurrent elevation of both markers emerged as the strongest independent correlate of bacterial etiology (OR = 8.74, 95% CI: 5.26-14.53, p < 0.001). CONCLUSION: The synergistic assessment of PCT with CRP surpasses individual marker performance for bacterial-viral pneumonia discrimination, capturing differential inflammatory cascades and severity stratification. This dual-biomarker strategy optimizes therapeutic decisions and antimicrobial governance.