Diagnostic precision in clinical laboratories: biochemical biomarkers and rapid microbiological methods for adult sepsis and bloodstream infection; a systematic review

Background: Discrimination of bacterial sepsis from sterile inflammation and early identification of bloodstream pathogens are important laboratory tasks. Biochemical biomarkers describe host response, whereas molecular assays and mass spectrometry detect or identify pathogens. Objective: To evaluate the diagnostic performance and clinical utility of biochemical biomarkers and rapid microbiological methods in adults with suspected sepsis or bloodstream infection. Methods: A search framework covering PubMed, Scopus, Web of Science, and Cochrane Library was applied to August 2026. Studies assessed C-reactive protein, procalcitonin, presepsin, multimarker panels, multiplex polymerase chain reaction, or matrix-assisted laser desorption time of flight mass spectrometry in adults. Outcomes included diagnostic accuracy, pathogen yield, identification time, antimicrobial optimization, length of stay, and mortality. Results: Ten studies involving 4,425 patients were included. Multimarker panels produced stronger discrimination in severe presentations than individual markers, while procalcitonin outperformed presepsin and C reactive protein for culture-confirmed infection. Multiplex polymerase chain reaction accelerated or increased pathogen detection but retained discordance with blood culture. Stewardship-linked rapid identification shortened therapy-optimization intervals. Clinical outcome effects were less consistent than workflow effects. Conclusion: Biochemical and microbiological methods provide complementary rather than interchangeable information. Diagnostic precision rests on validated assays, specimen quality controls, conventional culture, clinical context, specialist interpretation, and rapid communication.