Vol. 16 •Issue 2 • Page 31
Whirlwind of Changes in Store for Transfusion Medicine
Several promising techniques and technologies are set to streamline how blood is tested, processed and distributed across America.
From trauma to transplants and obstetrics to oncology, blood transfusions are vital to almost every branch of medicine. And that’s becoming truer every year, since the number of blood recipients rises 6 percent annually, and about 10 percent of all patients admitted to hospitals need blood transfusions.1
In fact, approximately 14 million units of blood are donated and distributed to 4.9 million needy patients annually across the country.2 On average, that means at least one transfusion occurs every two seconds, and around 38,000 units of blood are needed every day.
But despite blood’s increasing importance and seeming abundance, most blood centers and hospitals struggle to meet the transfusion needs of patients. Several upcoming trends, and hopefully some breakthroughs, may change that.
New methods and technologies for testing, storing and processing blood may increase its supply in America’s centers and maximize the number of lives that can be saved or prolonged through transfusion medicine.
New Tests, New Diseases
Blood centers test all donations for syphilis, hepatitis B and C, human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV) and West Nile virus. In the next few years, this list may expand dramatically.
Some consideration, for example, is being given to screen for malaria, says Paul Ness, MD, director of Transfusion Medicine at Johns Hopkins Medical Institutions and former president of AABB. While malaria is rarely found in the United States, the disease is a major problem in other parts of the world.
Additionally, a study recently conducted by the AABB in Southern California found a high incidence of Chagas disease there. Chagas, a parasitic infection that’s most prevalent in South and Central America, has infected 16 million to 18 million people worldwide.3
Because of the number of Latin American immigrants entering the United States every year, the FDA is expected to license testing for Chagas in the next few months. If that happens, blood centers across America could be testing for the infection by the end of 2007.
Transfusion-related acute lung injury (TRALI) is another, even more urgent issue within transfusion medicine. “TRALI is now recognized as the most frequent transfusion-related fatality reported to the FDA,” says Richard Benjamin, MD, PhD, chief medical officer of American Red Cross Biomedical Services in Washington, DC.
The FDA describes TRALI as a “clinical constellation of symptoms including dyspnea, hypotension and fever.” The condition is most often caused by the transfusion of leukocyte antibodies, and symptoms can fully manifest themselves within six hours.
In response to rising incidences of TRALI in the United States, the AABB recently released a bulletin outlining a plan to avoid the sometimes fatal condition. “We’ve known about this disease for 25 years,” says Dr. Benjamin. “But in the last few years, the United Kingdom has taken some steps to avoid TRALI, and they seem to have been effective.”
According to Dr. Benjamin, the United Kingdom reviewed data on TRALI four to five years ago, and found that TRALI is most often associated with plasma products donated by women. That’s because leukocyte antibodies are commonly found in women who have been pregnant one or more times—about 10-20 percent of the female population.
The transfusion industry in the United Kingdom concluded, and the AABB agreed, that one of the simplest ways to decrease incidents of TRALI is to avoid the transfusion of leukocyte antibodies.
While current tests for detecting leukocyte antibodies are prohibitively expensive, efforts to avoid the antibodies shouldn’t be difficult, thanks to an annual excess of plasma. “Because about 14 million units of whole blood are donated every year, and only 4 million units of plasma are used from those donations, we could earmark male plasma for transfusions and use female plasma to manufacture vaccinations and other products.”
Platelets are another matter, however. Because there’s no excess of platelets, the industry will need to develop new solutions to detect, screen and avoid leukocyte antibodies. Luckily, red blood cell transfusions contain little plasma and are of less concern. The AABB has given the industry about 24 months to make these changes, which could mean big changes for blood centers and laboratories across the country in the next two years.
Technologies on the Horizon
Beyond new-and-improved tests for an expanding variety of diseases, several institutions are also exploring strategies for neutralizing pathogens in blood. The process, known as pathogen reduction, is already being used in Europe and other parts of the world to virtually eliminate transfusion-related infections in both platelet and plasma samples.
Pathogen reduction is also “an effective way of inactivating white cells, which can cause adverse effects such as transfusion associated graft vs. host disease,” asserts Dr. Ness. The process is not yet licensed by the FDA, but an upcoming Canadian consensus conference on the subject of pathogen reduction may change that.
Dr. Benjamin says previous such conferences have been influential in introducing technology to the United States. If the FDA initiates steps to license pathogen reduction, blood centers will be employing new technology in the next few years.
One benefit the process is unlikely to provide, however, at least at first, is increasing the supply of usable blood in America. That’s because pathogen reduction probably won’t be used to sterilize donations that previously would have been thrown away, but rather to simply bolster current screening methods, says Dr. Benjamin.
Efforts to increase the amount of time blood components can be stored is another trend that could dramatically alter transfusion medicine. Some people question the importance of these efforts, though, since blood is rarely thrown away because it goes bad in storage. Aside from the excess plasma mentioned above, there’s actually a scarcity of blood.
According to Dr. Ness, however, there’s some evidence that blood decreases in quality the longer it’s stored. In addition, while red blood cells can be stored for up to 42 days (and longer if frozen), platelets can only be stored for five days. Increasing the shelf life of platelets even two days—as Gambro BCT’s PASSPORT protocol has done—has been of great benefit to patients.
Better blood substitutes represent another upcoming technology that could make our current blood supply go further, if not increase it. Several clinical trials are under way to study whether oxygen carriers could be transfused instead of real blood.
While these substitutes have been in development for decades, and there have been many disappointments along the way, they hold much promise. “I don’t see them replacing blood transfusions as we know them,” says Dr. Benjamin, “but they could be used in very specific circumstances for very short periods of times.”
Indeed, blood substitutes have been most commonly tested on patients in an ambulance on the way to the hospital. Part of the reason for that is because while blood can last as long as three months in the body, current blood substitutes rarely last longer than six hours. By necessity, therefore, these products could only be used in trauma, emergency or military situations. Even these limited applications, however, would be useful to hospitals and blood centers when more blood substitutes are approved for use.
No matter what new screening, sterilization or storage methods are on the horizon, one thing is clear: Technology will play an increasingly integral role in streamlining how blood is collected, processed and transfused in America.
Automation is one trend promising to increase productivity in transfusion medicine. “Right now we use a semi-manual method for testing, and there are fully automated machines that will revolutionize the testing and make it easier,” says Dr. Benjamin.
These machines also will allow for single-donor testing. The American Red Cross and other blood centers only have the ability to test eight to 16 samples at a time. While these automated systems—now being used in Europe and Africa—may not be available for one to five years, they could revolutionize how labs do their work.
The need for better identification systems is another pressing issue facing the industry today. The AABB has long recognized that human error—often errors of identification—account for a significant percentage of transfusion fatalities. Wristbands and labeling systems that include bar codes, radio frequency identification (RFID) technology and other tracking methods will become more prevalent in the next few years. Whether they are employed in the hospital or laboratory, these tracking systems should reduce the number of human errors involved in transfusions.
As mundane as it may seem, increased integration between the blood center and hospital pharmacy is another trend set to affect transfusion medicine.
Because of their increasing specialization, transfusions are becoming analogous to “prescriptions” from the “wet pharmacy,” says Dr Ness. So too is the expanding array of drugs developed from blood components. As the line between blood transfusion and prescription medicine starts to blur, better organization of these therapies will become an important consideration for administrators at hospitals, blood centers and labs.
Recruiting Donors and Lab Professionals
“Within the blood center, our greatest challenge is recruiting enough people to come in and give blood,” says Dr. Benjamin. Indeed, finding enough suitable donors has always been difficult, and it’s unlikely to change, since compensation and other incentives risk attracting donors of questionable motives with questionable blood.
What could change, however, are some of the FDA’s restrictions on who can donate blood. “We restrict blood donation a lot in this country,” Dr. Benjamin says. “And the possibility does exist that we could reduce some of those restrictions, depending on the development of better tests and pathogen reduction technology that’s on the horizon.”
Even so, the problem of finding enough donors will likely remain a challenge. That’s a disheartening fact, given another recruitment problem facing the industry: finding enough medical technologists willing to work in labs and blood centers.
There’s clearly no technological solution to these dual recruitment crises. No matter how technology improves storage, processing and transfusion techniques, the science of saving lives with blood will always rely on people, including the volunteers willing to donate blood and the professionals willing to administer it.
David S. Yankelewitz is a freelance writer in New York City.
1. 50 Quick Facts. Available at www.GiveLife2.org/sponsor/quickfacts.asp. Accessed Dec. 5, 2006.
2. FAQs About Blood and Blood Needs. Available at www.GiveLife2.org/aboutblood/faq.asp. Accessed Dec. 5, 2006.
3. Chagas. Available at www.who.int/ctd/chagas/disease.htm. Accessed Dec. 8, 2006.