Single-Site Sampling versus Multisite Sampling for Blood Cultures: a Retrospective Clinical Study

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Diagnostic Medicine

Background:

• Blood culture (BC) performance is crucial for sepsis diagnosis.
• Current sepsis guidelines recommend two sets of BC bottles (aerobic and anaerobic) but do not specify a sampling protocol.
• Single-site sampling (SSS) involves one venipuncture for all bottles, while multisite sampling (MSS) uses two separate venipunctures.

Purpose of the Study:

• To compare the diagnostic performance of SSS versus MSS for blood cultures.
• To evaluate differences in BC set collection, sample volume, and positivity rates between SSS and MSS protocols.

Main Methods:

• Retrospective clinical study comparing BC results before and after implementing SSS from MSS.
• Analysis of 5,248 patients under MSS and 5,364 patients under SSS.
• All BC samples were incubated using the BacT/Alert BC system.

Main Results:

• SSS showed a significantly higher proportion of positive BCs (19.56%) compared to MSS (17.76%) (P=0.018).
• This difference was attributed to fewer solitary BC sets collected with SSS.
• SSS had a higher proportion of bottles with recommended sample volumes (8-12 ml) than MSS (P<0.001).

Conclusions:

• Changing from MSS to SSS for blood culture collection resulted in higher positivity rates and improved sample volumes.
• SSS protocol demonstrated advantages in terms of diagnostic yield and sample quality.
• The benefits of SSS warrant consideration for inclusion in future sepsis management guidelines.