Likelihood of blood culture positivity using SeptiCyte RAPID.

Early diagnosis and identification of causative pathogens using blood culture in patients suspected of Blood Stream Infection (BSI) and sepsis are critical for improving patient outcomes through early and more targeted treatment. Methods: Post-hoc retrospective analysis of indiviudal patient data from three prospective clinical studies, conducted in North America, Europe and Africa, to investigate the association between SeptiCyte RAPID test results (SeptiScores) and blood culture results. Hypothesis: that a significant correlation exists between elevated SeptiScores and positive blood culture results, and between low SeptiScores and negative blood culture results. Results: As the SeptiScore increases, the relative probabilty of a septic patient being BC(+) as opposed to BC(-) also increases. A non-linear positive correlation is observed. Below SeptiScores of 10, the ratio of probabilities of BC(+) sepsis / BC(-) sepsis is <1 while above SeptiScores of 10 this ratio is >1. Thus, septic patients with SeptiScores >10 have a higher probability of being BC(+) compared to BC(-). Conclusions: Elevated SeptiScores, obtained before blood culture results, are indicative of increased blood culture positivity. This may have clinical utility, particularly in resource limited settings, as an aid for improving the efficiency of blood culture practice, for instance by informing patient selection and interpretation of blood culture results.