Correlation between blood volume, culture sets, and detection rates in bloodstream infections

Background: Blood culture remains the gold standard for diagnosing bloodstream infections (BSIs), with diagnostic yield influenced by variables such as blood volume, number of culture sets, and processing time. This study evaluates these factors and their impact on blood culture positivity rates using the BD BACTEC™ FX 40 system. Methods: A cross-sectional prospective study (June–December 2024) analysed blood cultures using BD BACTEC™ FX 40, assessing volume, sets, time to positivity (TTP), and organisms from laboratory records via standard microbiological methods. Results: A total of 2,016 blood cultures were processed, yielding an overall positivity rate of 28.67%. Cultures with adequate blood volume (≥8 ml per bottle) demonstrated significantly higher positivity rates compared to those with suboptimal volumes (p