Abstract
Lower respiratory tract (LRT) infections require rapid and accurate diagnosis. While bacterial culture remains the gold standard, multiplex PCR (mPCR) enables faster and more sensitive detection of multiple pathogens. This study evaluates the Bio-Speedy mPCR panel for 18 bacteria in comparison to conventional culture. A total of 100 LRT samples were analyzed. Complete concordance between the methods was observed in 85% of samples, with mPCR detecting pathogens slightly more frequently (62% vs. 53%). Discrepancies were primarily due to prior antibiotic therapy, low bacterial loads, colonization, or pathogens not included in the PCR panel. The sensitivity and specificity of mPCR were 79.3% and 96.8%, respectively, with negative agreement at 98.9% and positive agreement at 57.0%. Considering culture-negative but clinically relevant PCR-positive results, the sensitivity improved to 98.1% and the positive agreement to 86.7%. mPCR offers early pathogen detection, enabling timely therapy and potentially improving outcomes, particularly in intensive care settings. While culture remains indispensable for viable pathogen identification, combining mPCR with conventional methods provides complementary information, particularly when prior antibiotic use or the presence of fastidious pathogens may compromise culture results. Careful consideration of cost, patient population, and clinical context is recommended for optimal implementation of mPCR panels.