Test Detects Bacteria in Red Blood Cells

A highly sensitive culture-based test routinely used by blood centers to detect bacterial contamination of platelets is being used to detect bacteria that are commonly found as contaminants of red blood cells.

Pall Corporation (East Hills, NY, USA) has announced the CE marking of its enhanced bacteria detection system (eBDS) to detect bacterial contamination of red blood cells, the most widely transfused blood component. Since the availability of the Pall eBDS for detection of bacteria in platelets, there has been interest in applying the same technology to improve the safety of red blood cells. Recent studies have documented sepsis and death caused by transfusion of contaminated red cells, with the bacteria Yersinia enterocolitica most often implicated.

The Pall eBDS uses a novel approach to detection by measuring oxygen consumption as the marker for bacteria. If bacteria are present in the blood sample collected, an increasing amount of oxygen is consumed through the metabolic activity and proliferation of the bacteria during incubation, resulting in a measurable decrease in oxygen content.

In a study presented to the 29th International Society of Blood Transfusion (ISBT) 2006 Congress (Cape Town, South Africa), the Pall eBDS was tested on 662 red blood cell samples that had been inoculated separately with twelve different bacteria strains. Each sample was tested after 48 hours resulting in 100 % detection of the contaminating bacteria. Pall conducted this study in response to the need to reduce the problem of bacterial contamination of blood components.

Transfusion of a contaminated red blood cell, especially if contaminated by Gram-negative bacteria, is followed by a rapid onset of sepsis and greater than 60% mortality rate. Multiple studies have also documented a link between transfusions of red blood cells with nosocomial (hospital-acquired) infections. Critically ill patients who receive red cell transfusions are at increased risk of a nosocomial infection with a significant increase in mortality and/or length of stay in intensive care.

"Adding bacterial detection of red cells along with platelets can have a significant impact on the safety of the blood supply,” said Allan Ross, president, Pall Medical. "The blood centers that employ the Pall eBDS for platelet testing can simply and readily use it to detect bacteria in red cells. This is a highly cost-effective way to help them ensure they can provide the safest blood for transfusion.”

Some nations urge greater use of autologous red blood cells (a person's own pre-donated blood) for transfusion, especially for non-emergency surgical patients. It is not generally realized that autologous blood may not be free from bacteria and can become contaminated from environmental factors, skin contamination at the time of donation, or during the handling and processing after collection. Testing autologous red blood cells for bacteria will help conserve and supplement the blood supply to alleviate emerging blood inventory shortages.



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