Fast Assay for Pathogen Identification - Quasi-Experimental Intervention Study

Fast Assay for Pathogen Identification - Quasi-Experimental Intervention Study

The performance and clinical impact of two diagnostic systems will be evaluated using whole blood samples that are collected in parallel with samples for blood culture. As the rapid diagnostic systems will have the largest impact on severely ill patients (in need of a fast diagnosis) with bacterial infection, the evaluation will be performed in patients suspected of bacteraemia. During the study the new systems will be used in parallel with routine blood cultures. In alternating periods of 1 month, the results of the diagnostic system will be communicated to treating physicians (intervention) or not revealed (control). Blood culture results will be reported throughout the complete study period. Patients with suspected sepsis at the Emergency Department (ED), the department of infectious diseases/nephrology, and the department of haemodialysis will be included. In routine care, two blood culture sets (2x2 bottles) per patient are collected. One extra blood sample (EDTA tube, 9 ml of blood) will be sampled for each routine set of blood cultures. In addition, the clinical data of the patients will be collected. The samples will be sent to the clinical laboratory where samples are tested with the new systems during regular working hours in batches of 8 samples per run (2-3 runs per day). On average, 10%-20% of the blood cultures drawn on the presumption of bacteraemia yield bacterial pathogens. Previous data show that 13% of patients yield positive blood cultures. Thus, in order to collect blood samples of 100 new episodes of bacteraemia approximately 1000 patients (2000 blood cultures + 1000 EDTA tubes) have to be collected for each system (2000 patients in total). The results of the systems will be used to evaluate the clinical utility of the system regarding time to antibiotic treatment change and bacteraemia management. The system will be used directly for the diagnosis of patients, resulting in a possible change of treatment strategy. However, routine blood culture practices will still be done during the whole study period.

Inclusion Criteria:

• Suspicion of sepsis
• The drawning of blood cultures
• Age >18 years

Exclusion Criteria:

• Children (<18 years)
• Patients who are not hospitalized and sent home after ED admission
• Duplicate blood cultures from the same bacteraemia episode (7days between positives with the same organism, or 24h for different organisms)
• Patients from who blood cultures are drawn on Friday evening (17h) or Saturday during intervention periods