The correct blood volume for pediatric blood cultures: a conundrum?

Abstract Background Bloodstream infections (BSI) are a major cause of morbidity and mortality in pediatricpatients. For fast and accurate diagnosis, blood culture(BC) is the gold standard. However, the procedure for blood sampling in pediatricpatients, particularly the optimal blood volume, is the subject of controversy stemming from a lack of knowledge on the bacterial load and because of several obstacles such as low intravascular volume with the risk of causing anemia. Objectives The aim of this narrative review was to summarize current knowledge on blood sampling in pediatricpatients for BC purposes in particular on blood volume, number and type of BC bottles needed for reasonable future guidelines/recommendations. Sources A comprehensive literature search of PubMed including all English literature was performed in June 2019 using the search terms ‘ blood culture’, ‘ blood volume’, ‘bloodstream infection’, ‘diagnostic’, ‘ pediatric’ and/or ‘sepsis’. Content The amount of inoculated blood determines the sensitivity, specificity and time to positivity of a BC, and low-level bacteremia (≤10 cfu/mL) in pediatricpatients is presumed to be more common than reported. Current approaches for “adequate” blood volumefor pediatricBC are mainly weight- or age-dependent. Of these recommendations scheme devised by Gaur and colleagues seems most appropriate and calls for a sample of 1-1.5 mL for children weighing less than 11 kg and 7.5 mL for a patient weight of 11-17 kg to be drawn into one BC bottle. Inclusion of a more detailed grading in the weight range 4-14 kg as published by Gonsalves and colleagues might be useful. Implications This review could be important for future guidelines on pediatricBC collection and thus could contribute to improving patient management and lowering the economic and global health burden associated with BSI. Furthermore, upcoming molecular-based approaches with low sample volumes might be an interesting alternative.