Researchers from the University of Nebraska Medical Center (UNMC) have reduced false positive in patient blood samples by 88 percent with the SteriPath initial specimen diversion device (ISDD). Findings were published in the May issue of Clinical Infectious Diseases.

During the taking of blood drawings, contaminations routinely occur due to skin fragments containing bacteria in the sample. These false results lead to 30 to 40 percent of patients receiving unnecessary prescriptions, additional blood draws, extended hospital stays and potential antibiotic side effects.

"A lot of people think this is a minor problem," said Mark Rupp, MD, professor and chief of the UNMC Division of Infectious Diseases and medical director of the Department of Infection Control & Epidemiology at Nebraska Medicine. "However, contaminated blood cultures are a big deal. Physicians can be led astray and patients may be harmed by additional tests and unnecessary antimicrobial therapy."

The study included 904 patients and 1,808 blood samples. Results were compared using conventional methods and the ISDD device. The ISDD device is able to divert and sequester the first 1.5 to 2 milliliters of blood, which often contain the contained cells. Using the ISDD device, researchers were able decrease the amount of false positives by 88 percent using the ISDD device.

"If a midpoint cost estimate of $4,850 is used, and the added cost of the device is not taken into account, it equates to a cost avoidance of $1.8 million per year at our institution alone," Rupp said. "If the low rate of contamination that we observed in the study, 0.22 percent, was applied to all blood cultures throughout the country, billions of dollars of excess costs could be avoided. What is important about this device is it can greatly limit the blood culture from being contaminated, so physicians are rarely fooled by false-positive results. It gives clinicians confidence that results are accurate."