Evaluating the effectiveness of a two-set approach for improving blood culture positivity rates in dogs and cats.

Abstract

BACKGROUND: Sepsis diagnosis relies on the assessment of systemic conditions and blood cultures. Although the analysis of multiple blood culture sets improves the positivity rate in people, evidence supporting the use of multiple sets in dogs and cats remains limited. METHODS: In this retrospective observational study, anonymised data from feline and canine blood culture testing performed at a commercial laboratory in Japan were analysed. Positivity rates were calculated for one- and two-set blood cultures and compared using a sensitivity analysis, assuming contamination rates ranging from 0% to 100%. RESULTS: The positivity rates in dogs for the one-set (n = 1274) and two-set (n = 842) tests were 20.9% and 19.2%, respectively. This difference was significant only when false positives constituted 50% or more of the results. The proportions of cats in the one-set (n = 69) and two-set (n = 34) tests were 47.8% and 91.2%, respectively. The two-set tests in cats consistently showed significantly better positivity rates than the one-set tests, regardless of the number of false positives. LIMITATIONS: This is a retrospective study, and differences in processes between submitting veterinary practices may have affected the results obtained. Furthermore, no clinical data were available for the sampled animals, which limits the conclusions that can be drawn. CONCLUSION: In dogs, the positivity rate of blood cultures was approximately 20% regardless of whether a one-set or two-set test was performed. However, in cats, a two-set blood culture increased the positivity rate by approximately 50 percentage points, reaching nearly 90%.