Abstract

The differential diagnosis of bacterial pneumonia from viral or non-infectious pulmonary conditions remains a persistent clinical challenge, particularly in hospitals where advanced microbiological infrastructure is unavailable. Procalcitonin (PCT) and C-reactive protein (CRP) are widely regarded as complementary inflammatory markers, yet their practical usefulness in resource-constrained settings is rarely examined critically. This article revisits the diagnostic performance of both biomarkers, weighing their sensitivity, specificity, cost-effectiveness, and interpretive limitations in the context of low- and middle-income country (LMIC) hospital practice. We argue that neither marker alone is sufficient, that their combined use follows a context-dependent logic, and that clinicians working outside tertiary centers should apply threshold values with caution rather than automatism. A practical clinical scenario-based framework for prioritizing one marker over the other when resources are limited, alongside a cost-effectiveness analysis comparing biomarker testing with traditional approaches, is proposed.

Keywords

procalcitonin, C-reactive protein, community-acquired pneumonia, bacterial infection, resource-limited diagnostics, inflammatory biomarkers, antibiotic stewardship, LMIC