Blood plays a role in healthcare, serving in transfusions, surgical procedures, and the treatment of various medical conditions. Preserving blood effectively is important in modern medicine. Specialized storage methods ensure components retain their therapeutic properties.
Lifespan of Stored Blood Components
Different blood components require specific storage conditions and have varying lifespans to maintain their functionality. Red blood cells, important for oxygen transport, are stored at 1 to 6°C. They remain viable for up to 42 days when stored with appropriate additive solutions. Whole blood, while less commonly transfused than individual components, follows a similar storage protocol, viable for up to 35 days.
Platelets, important for blood clotting, are handled differently. They are stored at room temperature (20 to 24°C) with continuous gentle agitation to prevent clumping. This allows platelets to be kept for 5 to 7 days, as refrigeration can impair their ability to circulate and perform upon transfusion. However, recent research explores the benefits of cold-stored platelets for acute bleeding, where their enhanced hemostatic potential may outweigh concerns about a shorter post-transfusion survival.
Fresh frozen plasma (FFP) contains clotting factors and proteins. FFP is frozen within eight hours of collection and stored at -18°C or colder. This allows FFP to be kept for up to one year. Once thawed, FFP is stored at 1 to 6°C and should be used within 24 hours to ensure its clotting factors remain effective. Cryoprecipitate, another plasma-derived component rich in fibrinogen and other clotting factors, is also stored frozen at -18°C or colder for up to one year. After thawing, it is kept at room temperature and must be transfused within 4 to 6 hours.
How Blood Storage Works
Maintaining the viability of blood components relies on a combination of precise temperature control and specialized chemical solutions.
Refrigeration (1 to 6°C for red blood cells) slows down their metabolic processes. This reduced metabolic activity minimizes glucose consumption and waste product accumulation, preserving cell integrity and function.
Anticoagulants are important to prevent blood from clotting after collection. Common solutions, such as citrate-phosphate-dextrose (CPD) and citrate-phosphate-dextrose-adenine (CPDA-1), work by binding to calcium ions, which are important for the coagulation cascade. CPDA-1 contains adenine, which helps red blood cells maintain their energy (ATP) levels, extending their shelf life to 35 days.
Beyond anticoagulants, additive solutions are mixed with red blood cells to enhance their preservation. These solutions, including types like AS-1, AS-3, AS-5, and SAGM, provide nutrients such as glucose and adenine. They sustain the metabolic needs of red blood cells, reduce cellular stress, and protect their membranes, extending storage to 42 days. For components like plasma and cryoprecipitate that require freezing, methods involve rapid cooling to ultra-low temperatures, sometimes utilizing cryoprotectants to safeguard sensitive proteins and cellular structures from damage during freezing.
Ensuring Blood Quality and Safety
Maintaining the highest standards of quality and safety is important for all stored blood products.
Before any blood donation is accepted for storage or transfusion, it undergoes rigorous testing for various infectious diseases. This extensive screening includes tests for viruses such as HIV, Hepatitis B and C, Human T-lymphotropic Virus (HTLV), West Nile Virus, and Zika virus, as well as syphilis and Chagas disease. Blood typing (ABO and Rh) and antibody screening are also performed to ensure compatibility with potential recipients.
Once deemed safe, blood components are placed in highly controlled storage environments. Blood banks utilize specialized refrigerators and freezers that maintain precise temperatures, with continuous monitoring systems and alarm alerts for any deviations. This strict temperature control is important for preventing bacterial growth and preserving the components’ therapeutic properties.
Adherence to expiration dates is non-negotiable; blood components must be used within their specified shelf life. Using blood beyond its expiration date can result in a loss of function and an increased risk of adverse reactions for the patient. Regular quality control checks, including visual inspections for any abnormalities like discoloration or clots, are also performed. Any blood unit that has expired, fails a quality check, or is found to have a positive test result for infectious agents is immediately and safely discarded, ensuring that only suitable products are available for patient care.