Objective: To determine how switching to a sterile needle after phlebotomy and before the inoculation of blood culture bottles affects the rate of skin flora contamination.
Design: A randomized trial.
Setting: Medical inpatient services and the emergency department of a large university hospital.
Participants: Housestaff, medical students, nurses, and physician assistants who draw blood cultures on the general medicine, cardiology, and renal transplant units and in the emergency department.
Interventions: Phlebotomists were randomly assigned to draw blood cultures by either the conventional method or an alternative method in which the blood culture bottles were inoculated without switching needles.
Measurements and main results: There was no difference in the rate of contamination between the conventional technique (6 of 462 cases, 1.30%) and the alternative technique (7 of 451 cases, 1.55%) (95% CI for the difference in rates, -1.8% to 1.2%).
Conclusions: The needle switch in the conventional blood culture technique does not reduce the rate of skin flora contamination. Blood cultures should no longer be obtained by switching needles.