Jun 18, 2023Transfusion medicine is the branch of medicine dealing with the removal and/or transfusion of blood or blood components, including aspects related to hemovigilance. Transfusions between donors and recipients have existed for nearly four centuries, with most advances in the last 100 years. Patients undergo transfusions after major surgery, serious injury or in cases of serious health conditions like leukemia or kidney disease that lead to anemia. Transfusions are a very common procedure, with 85 million blood units transfused annually worldwide.
All record keeping and tracking requires the manual intervention of a staff member who must physically handle the blood unit to read and/or scan it. In transfusion medicine, blood units are individual units of red blood cells (RBC), plasma, platelets and other products managed under guidelines from the International Society of Blood Transfusion (ISBT), the scientific society promoting research and best practices in the field for nearly 90 years. Frequent use is also made of batch products managed under GS1 guidelines and derived from fractionation of plasma pooled sourced from multiple donors.
How Blood Is Managed
Graham Murdoch
Cold chain management of all blood components and batch products is extremely important but often unregulated. Bacterial contamination of platelets has been the greatest transfusion-transmitted infectious risk in recent years. The various blood products are stored at different temperatures and have varying shelf lives. RBC has a shelf life of between 35 and 42 days, depending upon its processing history, and is stored in special fridges and cold rooms at a temperature of 4 degrees Celsius +/- 2 degrees Celsius.
Bacterial growth is inhibited by the low temperature and enhanced if a unit is allowed to warm up. Plasma units are frozen, typically at -40 degrees Celsius, and are hard frozen for long-term storage at -80 degrees Celsius, which gives them a shelf life of years. Platelets have a shelf life of only five days and are stored at 22 degrees Celsius +/-2 degrees Celsius in agitators that keep them in gentle motion to prevent them from clumping or aggregating together. Storage at too high or too low a temperature will affect their usefulness.
RBC is moved from the hospital's blood bank fridges to blood-storage fridges located at critical care centers within a hospital, such as the operating theatres, emergency wards, or oncology and maternity wards. Daily stock takes of all units are required, as well as the recording of the times they are moved into or out of storage refrigeration. This is generally managed by written records, barcode scanning or a combination of the two.
Challenges Big and Small
Blood is a valuable resource that saves lives. With aging populations in many countries, the supply of donated blood is dropping while demand is increasing. Reducing unnecessary wastage is a challenge and important goal for blood administrators. In hospitals, each RBC unit is handled multiple times daily. On average, each RBC unit is handled more than 200 times before being transfused. Manual processes always carry the potential for mistakes to be made by users.
The principal challenge for paper and barcode systems is reliance on users following correct procedure at all times. Paper-based systems also face the challenge of illegible handwriting and delays in data entry. Manual data taken off paper records can result in handling problems not being identified until days after the event. Barcodes can avoid these particular problems.
However, correct data entry is still dependent upon users following the procedure correctly and scanning all units as and when required. If units are not properly scanned, there may be no way of knowing. Errors in scanning, or the incorrect removal or handling of a unit, cannot be captured by these systems as they do not provide real-time information.
The Journey from Vein to Vein
The gold standard is complete end-to-end traceability, from donation to transfusion. For a full audit trail, cold chain record-keeping and compliance is required at all times. This means knowing the real-time location of each blood unit in storage and movements into and out of storage, from the point of donation right up to transfusion into the patient.
The more times RBC units are handled and remain out of their refrigeration appliances, the greater the chance of dangerous bacterial growth and the risk of adverse patient outcomes. Pilot studies and analysis of critical incident reports have shown the potential for significant improvements in transfusion safety with a properly implemented radio frequency identification (RFID) system.
The Case for RFID
Real-time visibility provided by RFID can eliminate wastage through mishandling with automated error messaging and compliance enforcement. What is not well understood is that only 50 percent of wastage results from mishandling events. The remaining 50 percent of wastage results from the simple shelf-life expiry of units which fail to be needed for transfusion at a particular hospital.
Expiry management is further complicated by the unsuitability of older blood for older patients, the very young or critical-care patients. As blood ages in storage, it is useful for a progressively smaller group of patients. RFID can monitor both blood unit products and batch products, and for batch products it can individualize these products, providing a level of product control not possible with the existing GS1 product batch code only.
Manual and barcode systems require user action to record or scan units, and they only provide a snapshot of the units in storage at the time the units are being handled or scanned. In contrast, RFID can provide a continuous record of unit location information and temperature, providing a guaranteed record of compliance.
Studies have shown that moving blood between hospitals can eliminate expiry wastage by matching blood units to the local patient demand across a group of hospitals. Blood is currently not moved between hospital blood banks, except for rare phenotypes, because with existing paper and barcode systems, there is no guarantee that proper handling procedures have been followed at all times.
Also, integrating RFID into other transfusion equipment allows the possibility to further improve processes. For example, at the point of collection, an RFID reader integrated into the blood collector could record the donation timing and record the weight of a blood donation. Similarly, integrating an RFID reader into a transfusion stand would record the instant the transfusion starts and stops and track the correct placement and administration of a unit of blood at the point of transfusion. RFID-enabled devices can remove the reliance on operators taking specific activities and records to provide real-time visibility of operations.
RFID provides automated and unattended compliance and real-time visibility of all blood units in storage. In the case of written record keeping or barcode scanning, RBC units must be removed from storage and handled. RFID avoids this human intervention as the stock take is done automatically inside the fridge by the RFID system. With the appropriate software, inventory checks can be performed remotely and without attending the storage location for a full picture within seconds from the administrator's desk, for real end-to-end visibility from donation to transfusion.
Completely Eliminating Risk
RFID has the potential to completely eliminate avoidable human errors in blood transfusion. Manual and barcoded systems are only as good as the user entering or scanning the blood unit, whereas RFID provides real-time visibility of all units in storage and real-time visibility of all movements, including who actioned them, when linked with the storage device access control. This visibility is completely independent of the user following any proper procedures.
Units moved out of storage incorrectly are instantly identified with an RFID system, and the user can be instantly notified. If no suitable rectification is made, then automated alerts can be sent up the chain to laboratory and blood bank personnel. If units are incorrectly handled, the RFID system enables corrective action to be taken before a serious medical incident.
In particular, RFID can eliminate the processing, tracking and administration errors in transfusion defined in Serious Hazards of Transfusion (SHOT) reports. These include near-miss, anti-D immunoglobin errors, incorrect blood component transfusion, handling and storage errors, right blood right patient, avoidable transfusion, delayed transfusion, and over or under transfusion. These events account for more than 80 percent of all SHOT incidents, with the remaining related to adverse medical reactions or complications.
RFID You Don't Have to Work Around
The publicly available international air interface standard ISO 18000-3 for HF RFID incorporates two modes, Mode 1 and Mode 2. Mode 1 was a rebadged version of the legacy ISO standard ISO 15693, designed for unitary vicinity card applications such as access control or lift passes. Mode 2 was a totally new RFID technology based on phase jitter modulation (PJM), originally designed for high-speed bulk conveyor-fed item-level identification.
Mode 2 incorporated new methods of commanding tags, receiving tag replies and encoding tag data to achieve exceptional performance and still remains the highest-performance RFID system in class available. The key features of Mode 2 PJM RFID have been enhanced in the latest PJM RFID chips with the addition of ultra-low-temperature operation, dual-protocol PJM and Near Field Communication (NFC), optional LED for pick-by-light operation, and radiation hard memory able to withstand medical sterilization.
Unlike other types of RFID technologies, PJM RFID being compliant with ISO 18000-3 Mode 2 is entirely unaffected by liquids, making it ideal for the tracking of blood and blood products. PJM RFID provides stacking with seamless 3D operation, allowing blood units to be packed and stacked without any special procedures or requiring any changes to existing handling procedures or processes.
The extremely high read speeds means no slowdown in normal handling processes, and its reliability of operation and 100 percent read accuracy are an essential requirement for blood tracking. RFID tunnels, RFID retrofit components for blood storage appliances and open shelf for cold and freezer rooms provide reliable and 100 percent accurate tracking of blood supply chain and management of blood inventory.
RFID provides automated and unattended real-time visibility of all blood units in storage, removing the requirement for user action or intervention to capture data. With the right software, this can provide real end-to-end visibility from donation to transfusion, without requiring new or special handling procedures, while providing a continuous record of unit location information and temperature for a guaranteed record of compliance.
Graham Murdoch is the managing director of SATO Vicinity, an R&D Centre of Excellence for PJM RFID established by SATO Corp. He holds a bachelor's degree in electronics engineering, and a master's degree with a specialization in RFID and wireless powering systems from the University of Western Australia. Graham has been involved in the design of RFID systems since his time at university, and he has multiple international patents to his name. He was a co-author of the RFID air interface standard ISO 18000-3, recommended by the ISBT guidelines for the use of RFID in transfusion medicine. Graham was a co-inventor of the PJM RFID technology supported by ISO 18000-3 and is currently involved in the design of PJM RFID systems used for item tracking in transfusion, medical, jewelry, banking and gaming applications.
