Mastering blood cultures: the key to better outcomes

Blood cultures should be collected when a patient is suspected of having an infection, in particular in the case of sepsis (i.e. a severe infection, or an infection associated with organ failure), ideally before antibiotic administration. In addition, to using aseptic techniques, you also need to take into account sample volume and number of sets. National guidelines and recommendations stipulate that at least two sets of blood cultures (= two aerobic and two anaerobic bottles) should be collected with a volume of 8-10mL per bottle in adults (adequate blood volume for paediatric BC are mainly weight-dependent). The bottles should then be incubated in a blood culture analyser as soon as possible, ideally within a maximum of four hours.^1,2 

But is that the reality in clinical practice? Findings from recent surveys and audits are quite alarming. A 2018 NHS England and NHS Improvement survey1 demonstrated that 87% of sites took only one set (rather than the recommended two) and only 3% of UK sites incubated blood cultures bottles within four hours of collection. In 40% of cases, time from sample collection to incubation was more than 24 hours! Regarding the volume of blood, which is a key parameter to ensure detection of bacteremia or fungemia, the vast majority of Trusts (88%) did not measure the collected volume of blood and 41% had, in fact, never audited their blood culture workflow altogether.

Why it is everyone’s problem