Blood banks play the critical role of collecting, testing, separating, storing, and distributing donated blood to patients in need. Roughly 36,000 units of blood are donated per day, which are used to treat patients who have lost blood due to surgery or trauma, or who have diseases that affect the normal functions of their blood. 

Modern blood banks rely heavily on automation to streamline operations and prevent errors when processing blood. For example, donations of whole blood are typically separated into sub-components, like red blood cells, plasma, platelets, and other components. Alternatively, specific components of blood can be collected from a donor, with the remainder of the blood returned to them, allowing more frequent, higher volume donations of specific components (using apheresis). 

In this article, we’re going to focus on environmental monitoring in blood banks, particularly monitoring the temperature of storage areas like refrigerators, freezers, and temporary storage locations used during transit. This is an important topic because blood products must be stored and transported within a narrow temperature window to preserve them and ensure they’re safe for transfusion. 

Making matters more complicated, each of the sub-components of blood has a different set of required storage conditions. A monitoring strategy that is automated and can adapt to a diverse set of products can reduce risk and improve efficiency. Furthermore, blood banks are regulated by the FDA, and a comprehensive environmental monitoring system is needed to maintain regulatory compliance and maintain accreditation. 

Fortunately, modern electronic data loggers are well suited to meet the demands of a blood bank. Later in this article, we’ll talk about some of the monitoring equipment available for this application, and the best approaches for deploying it to minimize waste and ensure patient safety and regulatory compliance. Specifically, thermistor-based temperature loggers that wirelessly upload data to a central, cloud-based monitoring tool, represent the state of the art. 

Temperature Monitoring in Blood Banks

As we mentioned above, donated blood is usually stored and distributed as sub-components or blood products. Whole blood is sometimes also kept in blood banks, for example in the case of autologous transfusions where a patient donates blood for their own later use. 

The storage requirements for even the most common blood products are quite different:

• • Whole blood and red blood cells in solution (packed) are stored at 1-6 °C, and have a shelf life of 35 and 42 days, respectively 
  • Platelets are stored at 20-24 °C, for up to 5 days with light agitation
  • Plasma is normally frozen, and stored up to one year at < -18 °C
  • Cryoprecipitated AHF, which is produced when frozen plasma is thawed, can be stored for 1 year at < -18 °C

(These are fairly general guidelines. More specific information can be found in 21 CFR 601.53 for storage and 600.15 for transport.)

It almost goes without saying that the consequences of improper storage are serious. At best, if a temperature excursion is detected, valuable stored blood products are wasted needlessly. If an excursion isn’t detected, and an improperly stored blood product is transfused, there is a risk to patient health. 

Consider red blood cells (RBC), which are the most commonly used blood product. If RBC is stored above 6 °C, there is risk of bacterial growth; likewise, storage below 1 °C can cause hemolysis (physical destruction of the cells and release of hemoglobin), which can lead to serious reactions after transfusion.  

The blood bank plays a central role in ensuring that blood products are stored at a safe temperature. In a 2018 study, the temperature of 100 RBC bags was recorded every 2 minutes as the bag traveled from the blood bank to a cardiac surgical ICU. Roughly 10% of all temperature points were out of the standard range, with 65% of these points measured while the bag was in the blood bank- probably not surprising, since this is where the RBC bags spend the majority of their time. 

In another study, two methods were used to determine whether an RBC unit could be re-issued after being returned to the blood bank unused. One was a historical rule where an RBC unit that was outside of a temperature-validated storage container for more than 30 minutes would be discarded. In the other method, the temperature of the unit was directly measured, and any unit that rose in temperature to >10 °C at any time would be discarded. The temperature-based approach led to about 13% more units being discarded; however, this method also decreased the transfusion reaction rate significantly. 

These examples demonstrate the value of continuously measuring and recording the temperature of the storage areas used for blood products with reasonably high frequency, rather than relying on general rules of thumb. 

Why Selecting the Correct Environmental Monitoring System is Essential

Due to the extreme risk to human health, blood is stored and distributed using a cold chain, where refrigeration is maintained continuously from the point of donation to when it is used. This approach is also used in other temperature-sensitive products, like vaccines and perishable foods. 

One of the keys to maintaining a proper cold chain is continuous, accurate temperature monitoring in the locations where the products are stored and transported. This can be done a number of ways, including manual thermometer measurements, paper chart recorders, or digital data loggers. Manual recordings are problematic because they are susceptible to human error and don’t leave a complete data record. Chart recorders require consumables like pens and paper, require more maintenance, are bulky, and are not easily scaled up or networked. 

Digital data loggers are the preferred option, since they eliminate these issues. Furthermore, modern data loggers have a number of capabilities that make them a powerful component in a comprehensive environmental monitoring strategy:

• • Data upload to cloud-based storage, where it can be accessed from anywhere
  • Calibration status tracking for individual sensors
  • Customizable alarms that can be sent via SMS text, email, or phone call, helping to proactively avoid temperature excursions
  • Easily organized and automatically time-stamped data files
  • Customizable measurement parameters (useful when monitoring many different blood products at one site)
  • Easily scale-up by adding new monitoring points to an existing network
  • Software packages to visualize data and record corrective actions; units with touch screens can be used to quickly visualize data directly
  • Compact units, or units with external probes are well-suited to automate mapping, where the temperature of critical storage units is mapped in 3-dimensional space to characterize and reduce temperature variability
  • Design with regulatory compliance in mind

On this last point, in the US, blood banks are regulated by the CBER (Center for Biologics Evaluation and Research), which is part of the FDA. The federal regulations for blood banks, found in 21 CFR 600-680, are enforced through regular inspections, as described in CBER 7342.001. Modern digital data loggers are built to comply with these regulations. 

A review of FDA inspection citations over the last 10 years shows several instances where temperature monitoring and control, or lack of a written plan to control temperature was the basis for a citation. A thorough, comprehensive environmental monitoring approach, using networked digital data loggers, can avoid these types of issues. 

In addition to the FDA and WHO, the American Association of Blood Banks (AABB) publishes detailed standards for blood banks. Almost all of the blood used in the US is collected at AABB-accredited facilities (they also offer accreditation for facilities outside the US). AABB accreditation involves following a thorough quality standard, including continuous monitoring of blood storage locations with temperature data collected at least every 4 hours. This requirement is easily fulfilled when using automated digital data loggers to monitor temperature. 

Conclusions

Blood banks provide a life-saving service for millions of patients every year. Donors and recipients rely on blood banks to safely store and distribute a variety of blood products. The use of an automated environmental monitoring system using data loggers is an efficient and effective way to minimize waste, protect patients, and ensure regulatory compliance. 

Questions about environmental monitoring equipment or strategies? Contact the experts at Dickson.