The Light at the End of the Tunnel May be the Train
AABB'sStandardshave required "methods to limit and to detect or inactivate bacteria in all platelet components" for almost 10 years. In 2012, the Blood Products Advisory Committee (BPAC) voted that "additional measures are needed to decrease the current risk of transfusion of bacterially-contaminated platelet products," and FDA is writing guidance that will standardize our approaches. ABC centers are asking me about the pending guidance, but guessing the timing or content of agency guidance is not often fruitful; however, the options available aren't rocket science.
It is a good time to prepare for what is possible. A combination of the following are likely.
- Optimal skin preparation and diversion of the initial aliquot of blood to divert the (contaminated) skin plug for any platelet collection should already be in place.
- Early culture of apheresis platelets is essentially universal. Its sensitivity can be increased by extending the interval before culture inoculation; increasing the volume of product inoculated; extending the hold period after inoculation before product release.
- An ABC member proposes increasing the interval before culture inoculation beyond 24 hours for a proportion of collections, to two, three, or four days, arguing there is an interval of "bacterial safety" after culture (approximately 72 hours) that would allow negative units cultured later in storage an extended outdate to as long as seven days.
- Options for whole blood platelets are more complex and include culture as for apheresis after pre-pooling, and/or the use of point-of-release assays before release of pools for transfusion.
- Two approved devices are available for rapid retesting of culture-negative platelets before transfusion. They seem most suitable for use in the hospital.
- Shortening the outdate of platelets from five, to four or three days, avoiding the days of storage when most septic reactions occur was discussed at BPAC. There was recognition that this could result in platelet shortages.
- A pathogen reduction system for platelets is in the late stages of consideration by FDA. Some think approval could come in the next six to nine months. This might obviate the need for other strategies, and may allow discontinuing the culture-based testing (as has occurred in the EU), as well as point-of-release detection systems. There is no way to predict which current interventions may be affected or when their elimination might be feasible following FDA approval of a pathogen reduction system.
Louis Katz, MD, Chief Medical Officer; email@example.com