Prognostic Value Of Blood Cultures as an Illness Severity Marker In Emergency Medical Admissions.

BACKGROUND Positive blood cultures predict mortality. The prognostic value of blood culture performance itself has not been fully defined. METHODS We evaluated medical admissions from 2002-2017. We defined blood culture category as 1) no culture 2) negative culture 3) positive culture. We employed a multivariable logistic regression model to evaluate outcomes. RESULTS We evaluated 78,568 blood cultures in 106,586 admissions. 30-day in-hospital mortality for no culture was 2.8% (95%CI 2.7, 2.9), culture negative 8.9% (95%CI 8.5, 9.3) and culture positive 16.7% (95%CI 15.5, 17.9). There was significant interaction between blood culture category and illness severity, OR 1.06 (95%CI 1.05, 1.08), and comorbidity, OR 1.09 (95%CI 1.09, 1.10). CONCLUSION Performance and results of blood cultures are independently associated with increased mortality.