Vol. 13 •Issue 6 • Page 54
Trends in Transfusion Medicine
Improved blood bank procedures and advanced technologies have decreased the risk of transfusion-transmitted diseases.
The quest to reduce transfusion-transmitted diseases has come to the forefront of blood bank issues in recent months. With the new AABB and CAP standards for reducing platelet bacterial contamination comes increased awareness and concern. Health professionals in many areas are focused on safeguarding our nation’s blood supply.
Challenges of Transfusion Medicine
At a meeting of the Department of Health and Human Services Advisory Committee on Blood Safety and Availability in 2003, the committee recognized that the leading causes of transfusion-related fatalities are:
•bacterial contamination of platelets,
•hemolysis due to errors and
•transfusion related acute lung injury (TRALI).1
They also recognized that efforts to address these threats have been limited in comparison to other threats. The committee further recognized that public attention remains highly focused on residual risks from HIV and hepatitis agents, and that technologies already exist that could effectively reduce the risk of bacterial contamination and hemolysis.
Mark E. Brecher, MD, professor, Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, tells ADVANCE that a major challenge physicians and laboratorians face is implementing mandated safety measures (e.g., nucleic acid amplification technology [NAT] testing, bacterial testing) without a timely increase in reimbursement for blood products.
Supply and demand is also on the minds of some. Louis Katz, MD, president, America’s Blood Centers, Washington, DC, says that a major challenge of transfusion medicine is simply ensuring enough blood stays on the shelf. “Recruiting the right donors, selecting and using the right components for patients and patient identification are ongoing challenges,” Dr. Katz explains. “The public remains focused on the traditional infectious risks (HIV and hepatitis) that have been controlled, while blood bankers understand that the noninfectious serious hazards of transfusion (NISHOT) such as TRALI, which occurs in about 1 in 5,000 transfusions, are more important.”
The rising cost of blood components fueled by the need to make blood safe from infectious disease is a major challenge, says Suzanne H. Butch, MA, CLDir, chief technologist, Blood Bank and Transfusion Service, University of Michigan Hospitals, Ann Arbor. “Another challenge is making the process of transfusion safer–from specimen collection to transfusion. There is hope that with the FDA’s new emphasis on bar coding and the JCAHO’s concern with patient safety and patient identification that real progress will be made in the arena in the next few years,” she adds.
Regulatory issues such as billing correctly and complying with current Good Manufacturing Practices are important as well, Butch explains. She notes that other challenges in the laboratory include the lack of 1.) computer systems with sufficient error prevention and detection devices and 2.) interfaces to automated equipment.
Every year, approximately 4 million platelet units are transfused within the United States (1 million single donor apheresis platelets and 3 million whole blood derived platelet concentrates). Multiple studies have shown that 1:1000 to 1:2000 platelet units are bacterially contaminated (as measured by aerobic cultures). Therefore, it would be expected that 2,000Ð4,000 bacterially contaminated units would be transfused. 2
Says Dr. Brecher, three major factors have led to the decrease in risk of transfusion-transmitted diseases:
•better donor screening questions,
•enzyme-linked immunosorbent assay (ELISA)-based and NAT-based viral screening assays and
•bacterial screening of platelets.
Screening tests are performed for evidence of hepatitis B surface antigen (HBsAg); antibodies to the hepatitis B core (Anti-HBc); antibodies to the hepatitis C virus (Anti-HCV); antibodies to the human immunodeficiency virus, types 1 and 2 (Anti-HIV-1, -2); antibodies to human T-lymphotropic virus, types I and II (Anti-HTLV-I, -II); syphilis; NAT testing for HIV-1 and HCV; and NAT for West Nile Virus (WNV).
Dr. Katz feels that the standard serologic antibody and protein tests have contributed to the decrease in risk of transfusion-transmitted diseases, and NAT testing has had a big impact in detecting WNV. “Techniques today are more automated and technically sophisticated,” he explains.
Because NAT detects a virus’ genetic material–instead of waiting for the formation of antibodies, as with many current tests–it offers the opportunity to reduce the period when an infecting agent is undetectable by traditional tests, thus further improving blood safety.3 NAT was implemented in 1999 under the FDA’s Investigational New Drug (IND) application process. NAT for HIV and HCV was licensed by the FDA in 2002.
Butch agrees that NAT testing for HIV and HCV has decreased the risk of those diseases being spread through transfusions. “The blood bank community is fortunate to be able to discontinue doing p24 antigen testing for HIV, as this test contributed little to narrowing the window where a donor is infectious but does not yet test positive,” she tells ADVANCE. “The need to continue doing WNV testing once the disease has swept through the country and is no longer of general concern remains to be seen.”
Proper storage also is critical for error prevention. Blood banks should have an alarm tied into the operator system or interior maintenance system. If the alarm goes off in the blood bank, the entire lab should hear it. If storage areas are outside of the blood bank area, they should be tied into the same system as the blood monitoring systems. Other suggestions:
•.Validate your system and perform quality control checks on a regular basis.
•.Ensure alarm set points are inside the temperature range.
•.Define what time period is too long, and have clear-cut procedures of what staff should do if the alarm sounds (notify supervisor first, move products). For example, would the lab have enough time to move products to an alternate location if the alarm goes off? Clear guidance for all blood bank shifts is needed.
•Know the capacity of the unit–don’t go over the maximum.
•Ensure you are handling all products the same way. The monitoring system for platelets should be tied into the same system used for red cells.
Each unit of whole blood normally is separated into several components. Red blood cells may be refrigerated for a maximum of 42 days, or they may be frozen for up to 10 years. Platelets are stored at room temperature and may be kept for a maximum of five days. Fresh frozen plasma is kept in a frozen state for usually up to one year.3
Facing New Obstacles
The onset of new diseases such as WNV increases the need for improved screening methods. The first cases of WNV linked to blood transfusions were documented in 2002. Six transfusion-transmitted WNV cases were reported to the CDC in 2003. These cases involved blood donated by donors with low levels of the virus not detected by WNV testing. The most current (November 2003) approximate per-unit risk of transfusion-transmitted WNV is likely less than 1:1,000,000 (Table).
Blood Systems Laboratories, Tempe, AZ, introduced NAT screening of blood donors for WNV, which has detected a substantial rate of viremic donations, thus preventing recipient infections.4
Experts agree that automation–patient identification, in particular—will play a significant role in decreasing errors.
“Clearly, the way to minimize the risk of a mistransfusion is to computer identify (e.g., bar code) all patients, tubes and blood bags in a hospitalwide system that would give warnings at every step from vein to transfusion. This will undoubtedly come in time,” Dr. Brecher tells ADVANCE. “In terms of bacterial contamination, this is in some contexts already being addressed with semi-automated bacterial screening systems.”
Dr. Katz agrees, adding, “Barcode identification and radiofrequency devices that are electronically accessible identifiers can help reduce human error and the incidences of mismatched transfusion. It is critically important that the wrong blood doesn’t go to the wrong patient.”
Butch explains that automation allows staff to do other testing or be more cost effective. “Automation of patient identification will enhance, but cannot replace, good identification and re-identification procedures,” she says.
“Blood banking is historically a very manual science,” notes Brian Keefe, MT(ASCP), director of Product Marketing, Clinical Systems, Psyche Systems Corp., Milford, MA. “Any workup was historically done on grid sheets used by lab techs who recorded patients’ information (e.g., compatibility reactions). There is room for transcription error when one tech is working up more than one patient at one time.”
Psyche Systems offers its Systematic Blood Bank (SBB) Package, an online version of the grid sheet (see related article). “Blood banks are responsible for identifying inventory from the Red Cross and documenting any component issued to the patient. A lot of blood banks I visit need this information at their fingertips,” Keefe says.
Keefe explains that because blood banks are historically not computerized, there has been some degree of resistance to automation. However, “There is no stopping automation as it gets more sophisticated and faster,” he tells ADVANCE. “The FDA is involved in the validation process for automation, and there is resistance from smaller community hospitals, especially. It is hard to trust technology to handle a science that is life and death. In blood banking, you can actually kill someone.
“The SBB system does not teach you to be a blood banker. The system works with the knowledge the blood banker has. The system enhances what a blood banker does,” Keefe says. Psyche’s SBB system is designed to have online documentation of what blood bankers do.
He also says that there has been a stigma associated with the term “automated blood bank.” But automation in blood banks is becoming more accepted and trust in automation is growing. “Technology does not go in reverse,” he says. “When gas prices go up to $5 or $6 a gallon, we are not going to be driving around in horses and buggies.”
Blood banks have lagged in automation, but Keefe believes the cost of automation will come down and more laboratories will adopt it. And smaller rural facilities will eventually have to rely more on automation because of staff shortages. “The blood bank will be revolutionized as the rest of the clinical lab has been by automation.”
But, as Keefe explains, “Blood banking is a life and death science. Especially in a blood bank, software will never be able to completely replace the human element.”
Wyndgate Technologies offers its SafeTrace Tx (patent pending) advanced transfusion management system (see related article). “All transfusion services can benefit from enhanced efficiencies related to SafeTrace Tx’s capabilities for electronic and remote serologic crossmatching using an advanced compatibility check between donor and patient,” says Patti Larson, MS, MT(ASCP)SBB, senior director, Marketing Development, Wyndgate Technologies, El Dorado Hills, CA. “A remote serologic crossmatch enables a transfusion service to crossmatch a blood product at a central location and release it to a patient at a remote location virtually simultaneously.”
The ability to perform electronic crossmatches further enhances the efficiency of the transfusion service by reducing the time required to provide compatible red cell products, she explains. If an electronic crossmatch is performed for a qualified patient at the time the product is dispensed, unnecessary testing can be reduced, in turn reducing charges to the patient and providing better inventory management.
“Billing transactions are generated automatically as the technologists complete their work, providing accurate real-time billing. In an era where reimbursements have been reduced, ensuring that all of the billing charges are captured accurately takes on new importance,” she says. “Comprehensive safety checks throughout the process of testing, selecting and dispensing blood products help to ensure the suitability of the blood product for the patient.”
“Keeping laboratorians up-to-date on technological advancements involves having the time to train them. The training has to be identified and supported,” Dr. Katz says. He also says that training in a highly automated area such as transfusion medicine is critical. The skilled training will also make the position more attractive to job seekers.
To keep abreast of technological advancements to reduce transfusion risks, Dr. Brecher suggests following current literature and subscribing to blood bank journals and weekly summaries. Butch suggests that vendors need to exhibit at meetings, visit clients and provide product literature that focuses on the safety aspects of their products.
The Future of Transfusion Medicine
Dr. Katz feels more automation will exist in the future of transfusion medicine. “Laboratories are doing a good job now of process control, but that should be extended to hospitals and the bedside.”
“The transfusion service computer system needs to be developed with more error prevention and detection capabilities,” Butch adds. “This will take time because of the need for 510(k) premarket approval.”
And although a hemoglobin substitute may become available, it will not replace the need for transfusions as we know them today, explains Butch. “New infectious diseases will be found, tests created to detect them and more donors lost. Although work is being done on viral and bacterial inactivation of blood components, the problem of lack of effectiveness and unintended reactions is daunting,” she says.
“We have never been very good at predicting the future,” Dr. Brecher adds. “However, it is clear that blood will continue to be an essential part of modern medicine, and it will continue to become safer.”
Susan Hopkins is an assistant editor.
1. Department of Health and Human Services Advisory Committee on Blood Safety and Availability, 18th Meeting, January 2003, Washington D.C. Prioritizing decisions in transfusion medicine: Transfusion transmissible diseases. Accessed: http://www.hhs.gov/bloodsafety/transcripts/20030124.html
2. Brecher ME and Hay SN. Improving platelet safety: Bacterial contamination of platelets. Current Hematology Reports 2004;3:121-127.
3. American Association of Blood Banks. Facts about blood and blood banking. Accessed: http://www.aabb.org/All_About_Blood
4. American Society of Hematology. Breakthroughs lead to better understanding in prevention of transfusion-transmitted infection. Accessed: http://www.hematology.org/news/press