Biomarkers and molecular analysis to improve bloodstream infection diagnostics in an emergency care unit.
Molecular pathogen detection from blood is still expensive and the exact clinical value remains to be determined. The use of biomarkers may assist in preselecting patients for immediate molecular testing besides blood culture. In this study, 140 patients with ≥ 2 SIRS criteria and clinical signs of infection presenting at the emergency department of our hospital were included. C-reactive protein (CRP), neutrophil-lymphocyte count ratio (NLCR), procalcitonin (PCT) and soluble urokinase plasminogen activator receptor (suPAR) levels were determined. One ml EDTA blood was obtained and selective pathogen DNA isolation was performed with MolYsis (Molzym). DNA samples were analysed for the presence of pathogens, using both the MagicPlex Sepsis Test (Seegene) and SepsiTest (Molzym), and results were compared to blood cultures. Fifteen patients had to be excluded from the study, leaving 125 patients for further analysis. Of the 125 patient samples analysed, 27 presented with positive blood cultures of which 7 were considered to be contaminants. suPAR, PCT, and NLCR values were significantly higher in patients with positive blood cultures compared to patients without (p < 0.001). Receiver operating characteristic curves of the 4 biomarkers for differentiating bacteremia from non-bacteremia showed the highest area under the curve (AUC) for PCT (0.806 (95% confidence interval 0.699-0.913)). NLCR, suPAR and CRP resulted in an AUC of 0.770, 0.793, and 0.485, respectively. When compared to blood cultures, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for SepsiTest and MagicPlex Sepsis Test were 11%, 96%, 43%, 80%, and 37%, 77%, 30%, 82%, respectively. In conclusion, both molecular assays perform poorly when one ml whole blood is used from emergency care unit patients. NLCR is a cheap, fast, easy to determine, and rapidly available biomarker, and therefore seems most promising in differentiating BSI from non-BSI patients for subsequent pathogen identification using molecular diagnostics.
Jeroen Bosch Hospital, Laboratory of Molecular Diagnostics, 's-Hertogenbosch, The Netherlands ; Fontys University of Applied Sciences, Department of Medical Molecular Diagnostics, Eindhoven, The Netherlands.
Anne J M
AJ
Loonen
Jeroen Bosch Hospital, Department of Intensive Care and Emergency Medicine, 's-Hertogenbosch, The Netherlands.
Cornelis P C
CP
de Jager
Jeroen Bosch Hospital, Department of Intensive Care and Emergency Medicine, 's-Hertogenbosch, The Netherlands.
Janna
J
Tosserams
Jeroen Bosch Hospital, Department of Clinical Chemistry and Haematology, 's-Hertogenbosch, The Netherlands.
Ron
R
Kusters
Jeroen Bosch Hospital, Jeroen Bosch Academy, 's-Hertogenbosch, The Netherlands.
Mirrian
M
Hilbink
Jeroen Bosch Hospital, Department of Medical Microbiology and Infection Control, 's-Hertogenbosch, The Netherlands.
Peter C
PC
Wever
Jeroen Bosch Hospital, Laboratory of Molecular Diagnostics, 's-Hertogenbosch, The Netherlands ; Fontys University of Applied Sciences, Department of Medical Molecular Diagnostics, Eindhoven, The Netherlands.
Adriaan J C
AJ
van den Brule
D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D004632:Emergency Medical Services / Q000379:methods*; D006801:Humans; D018655:Lymphocyte Count; D009504:Neutrophils / Q000166:cytology; D011498:Protein Precursors / Q000097:blood; D012372:ROC Curve; D055293:Receptors, Urokinase Plasminogen Activator / Q000097:blood; D012680:Sensitivity and Specificity; D018746:Systemic Inflammatory Response Syndrome / Q000175:diagnosis*
D015415:Biomarkers; C000606589:CALCA protein, human; C524898:PLAUR protein, human; D011498:Protein Precursors; D055293:Receptors, Urokinase Plasminogen Activator; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide