Higher nursing care level is associated with higher incidence of blood culture contamination in the emergency department: A case–control study

Abstract

BackgroundBlood culture is critical in treating infectious diseases, but contamination occurs in 0.6-12.5% of all samples. This leads to unnecessary intervention, inappropriate antibiotic use, and excess cost. Few studies have tackled patient factors, such as nursing care level, that could possibly affect contamination rates. Thus, this study aimed to explore the association between patients' nursing care levels and blood culture contamination. MethodsThis is a single centered, retrospective, case-control study of adult patients whose blood culture specimens were taken in the emergency department between April 2018 and July 2019. The study was conducted in a 344-bed, urban, acute care community hospital in Chiba prefecture, Japan. We included patients aged 20 years and above, with two or more sets of blood cultures. The case group included patients with false positive blood culture results with contamination; the control group included patients with true positive or true negative blood culture results without contamination. We randomly selected two control patients per case. Patients' age, sex, nursing care level, ambulance usage, housing status, Glasgow Coma Scale, and hospital arrival time were obtained from the patients' medical charts. ResultsOf the 5,130 patients, 686 patients got positive blood culture results. Of the 686 patients, 35 patients were included in the case group, and 70 were randomly selected from the non-contaminated group and included in the control. In multivariate analysis, patients with contaminated blood cultures had a higher nursing care level (odds ratio: 5.24; 95% con dence interval: 1.47 to 18.70; P = 0.02). ConclusionsA higher nursing care level is associated with a higher incidence of blood culture contamination in the emergency department. Careful and appropriate procedures are required for patients with a higher nursing care level.