The current contamination rate is not known but has been estimated as high as 0.3%. Measures taken to reduce bacterial contamination of blood components include donor screening, improved skin disinfection, diversion of the first aliquot of blood from a donation into a pouch used for infectious disease testing, and requiring the testing of all platelet components for bacterial contamination. Adopting a bacterial detection test within 24 hours of issuing Platelets and using pathogen reduction technology may reduce the incidence of septic reactions.
Screening donors is done by questioning them about fever occurrence and dental or medical procedures that occurred days before donation. Donors who develop symptoms of an infection may be asked to notify the blood bank. Complete skin disinfection is not possible because of organisms living in places that are inaccessible, such as sebaceous glands and hair follicles. Factors affecting skin disinfection are the type and concentration of antiseptic, use of single or multiple antiseptics, method and steps of application, and contact time. Studies have shown that a two-stage method using a sponge scrub and ampule with a tincture of iodine is the most effective method. The AABB recommends an initial 30-second scrub with a 0.7% iodophor solution followed by applying a 10% iodophor compound, which must be allowed to dry for 30 seconds. To avoid normal flora contamination, blood may be diverted into a satellite bag at the beginning of donation. These bags are developed so that backflow is prevented. Blood contained in the satellite bag is used for blood grouping and infectious disease testing. Blood diversion is not a mandatory practice in the United States.
The AABB requires that the transfusion service have a method to detect bacteria in all platelet components. Culture-based methods are used at blood collecting facilities near the time of collection. Hospital-based transfusion services use other less costly non-culture-based methods such as gram staining or pH and glucose analysis before releasing the product for transfusion. Recently, a qualitative immunoassay for detecting bacteria in platelets has been developed. This test detects antigens on the cell walls of the bacteria. It has been documented to be more sensitive than other non-culture-based methods.
