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Diversion device reduces blood culture contamination, costs
A device that separates a portion of blood taken from patients significantly reduces culture contamination and can reduce the harm of unnecessary treatment, according to a study.
An initial specimen diversion device (ISDD) is used to separate from a sample the first 1.5 to 2 mL of blood, which presumably contains skin cells with contaminants, researchers wrote in Clinical Infectious Diseases.
“Reduced blood culture contamination should result in decreased costs and improved clinical outcome measures,” Mark E. Rupp, MD, medical director of the department of health care epidemiology-infection control at the University of Nebraska Medical Center, and colleagues wrote. “The very low rate of contamination observed in our study may justify abandonment of the current practice of performing two separate venipunctures ... which would result in improved patient satisfaction and health care provider safety.”
The prospective, controlled, open-label trial included blood cultures taken between November 2014 and October 2015 from 904 patients in the ED and trauma center of the researchers’ Omaha hospital. Two samples were taken from each patient, one using ISDD and the other using the standard hospital procedure.
Contamination was found in two ISDD samples (0.22%), compared with 16 (1.78%) standard procedure samples (P = .001).
There was no significant sensitivity difference, as the researchers found true bacteremia in 65 (7.2%) ISDD samples and 69 (7.6%) standard procedure samples.
A positive ISDD culture had a 97% chance of being a true positive, compared with 81% for standard procedure samples.
The accuracy offered by ISDD sampling can decrease adverse effects of unneeded antimicrobial treatment and other costs related to blood culture contamination, the researchers said.
They found that 407 (2.6%) of the 15,442 cultures taken in their hospital during the 6 months before and 6 months after the study were contaminated. They noted other studies showing contamination-related costs that ranged from $1,000 per case in 1998 to $8,700 per case in 2009.
“If a midpoint cost estimate of $4,850 is used, and the added cost of the [ISDD] is not taken into account, it equates to a cost avoidance of $1.8 million per year at our institution,” they wrote.
In a related editorial, Alexander J. McAdam, MD, PhD, director of the infectious diseases diagnostic laboratory at Boston Children’s Hospital, agreed that ISDDs can make blood culture processing more efficient.
“The study by Rupp [and colleagues] is valuable, as it provides us with a better understanding of an effective tool for reducing blood culture contamination,” he said. “The complete process of a laboratory test includes collection of the specimen, and our approach to specimen collection should, to the extent possible, be made in light of what we know or can expect in terms of cost and clinical outcome.” – by Joe Green
Disclosure: Rupp reports that he has received research funding from, and served as a consultant for, 3M.