Technology of a high-performance blood bank refrigerator

As the world’s population grows each year, the need for blood components continues to escalate. According to the American Red Cross, every two seconds, someone in the United States needs blood. And one of society’s most important priorities is to ensure that a safe, adequate supply of blood and blood products exists to meet this demand. There is no alternative product that can replace human blood, and the supply depends entirely on voluntary donations, which never fully meet demand. This supply constraint, coupled with the limited shelf-life of blood components, often make it difficult for blood centers across the U.S. to establish stockpiles and maintain more than a few days’ supply to meet routine transfusion demands. Every drop of blood is critical, and blood centers can’t afford to throw away product that was stored improperly and thus no longer meets the stringent guidelines set by the Food and Drug Administration (FDA), American Association of Blood Banks (AABB), and other regulatory bodies. Refrigeration innovations are crucial to protect the efficacy of this indispensable supply. 

History of blood banking and refrigeration¹

The first blood transfusions had to be made from donor to receiver, in a vein-to-vein fashion. In 1914, Drs. Albert Hustin of Brussels and Luis Agote of Buenos Aires discovered almost simultaneously that sodium citrate inhibits blood clotting.² The next year, Dr. Richard Lewison at New York’s Mount Sinai Hospital determined anti-coagulant concentrations that were safe for the recipient, while Dr. Richard Weil showed the feasibility of cold storage of anti-coagulated blood.³ The establishment of the first “blood depot,” a precursor of modern blood banks, is often credited to Oswald H. Robertson, a British medical researcher who served during World War I.⁴

Technology: the key to utilizing every drop of blood

Standards for blood banking have evolved with medical and technological advances. In the U.S., the collection and processing of each blood product is performed under specific standards to maximize transfusion efficacy. Most blood for transfusion is collected as whole blood (WB), or venous blood with an added preservative, and then separated by centrifugation into different components, such as red blood cells, plasma, cryoprecipitated antihaemophilic factor (AHF), and platelets. One unit of whole blood, after separation, may be transfused to several patients, each with different needs. “Packed red blood cells” (pRBC) are the most commonly transfused product. 

High performance refrigeration plays a large role in storage. Units of WB and pRBC must be stored at 1.0-6.0 °C, for a maximum permitted period of 35 and 42 days, respectively. Blood plasma is processed into a variety of components and has more stringent preparation and storage requirements in order to preserve the clotting factors. Once separated from the whole blood collection, plasma is placed in a specially designed blast freezer to rapidly freeze the plasma to −18 °C or colder. It is then placed in a plasma freezer where it is typically stored at −30 °C for up to one year. 

Blood banks, crucial in bringing the life-saving benefits of transfusion to patients in need, are of key importance in medical logistics, ensuring the availability of safe and effective blood components in a timely manner. The easiest way to accomplish this is to have an appropriate inventory of product of optimal quality on the shelf at all times, and highly specialized refrigeration equipment is critical to achieve this.

High performance refrigerator and freezer design

Blood bank refrigerators and plasma freezers feature stringent security measures to prevent tampering, and should meet all American Association of Blood Banks (AABB), American National Red Cross (ANRC), and/or FDA requirements.⁵ Unlike refrigerators and freezers for domestic use, high performance blood bank refrigerators and plasma freezers have specialized technical features:

1. High quality cabinet construction, with heavy walled, CFC-free insulation, helps to minimize energy use and ensure temperature stability.  
2. Time and temperature sensitive auto-defrost cycles, with automatic condensate removal, minimizes equipment downtime.
3. Stainless steel roll-out drawers and insulated, self-closing glass doors allow users to easily view and access product inside of the refrigerator.  
4. Forced air circulation that is both directed and monitored helps maintain uniform temperatures at all points in the cabinet and ensure quick temperature recovery after door openings.
5. Two in-chamber temperature probes allow for compliance with blood banking standards and provide an idea of cabinet temperatures at multiple points. Built-in or freestanding chart recorders are also used to comply with FDA documentation requirements.

Features of temperature monitoring systems

Because the required storage temperatures of blood products need to be maintained 24/7 and can be subjected to different variables (frequency of door openings, product load density, power outages, and changes in room temperature), the accuracy of the temperature control systems used in blood bank refrigerators and plasma freezers is crucial. Microprocessor-based control is the most advanced, precise, and reliable technology for controlling and maintaining temperatures. The onboard monitor makes provisions for alarm conditions through both audio and visual indicators, tracking events such as open doors, temperature deviations, and power failures. Battery backup capabilities are also essential, to ensure full alarm functionality in the event of a power failure.

As technology has evolved, so has the way users can monitor and interact with their precious cargo. High-performance blood bank refrigerators and plasma freezers are compatible with external, wireless monitoring solutions. These systems are designed to monitor critical parameters, including temperature, relative humidity, CO₂ concentration, and differential pressure. In the event of a power or mechanical failure, the wireless monitoring device instantaneously notifies users through audio/visual alarms, email, text message, telephone and fax. All of the data that is being monitored is continuously recorded to meet various regulatory requirements.

Every drop of blood is a precious resource. Choosing high performance products, like the technology currently available in cold storage equipment, is a critical step in maintaining the blood supply. New refrigeration technology incorporates features like precise temperature performance, continuous monitoring solutions, and data logging capabilities that are critical for blood banks to deliver blood products in their most potent form to patients in need.