Donated blood plays a central role in modern medicine, supporting transfusions for surgeries, trauma care, and various medical conditions. Blood banks are responsible for collecting, processing, and storing these donations, making them available when patients need them most. Donated blood has a limited shelf life, which varies significantly depending on the specific blood component. Maintaining the quality and safety of these components during storage is a complex and highly regulated process.
Shelf Life of Blood Components
Each component derived from a single blood donation possesses a distinct shelf life. Red blood cells, which transport oxygen, have a shelf life of up to 42 days when stored with specific preservative solutions. Platelets, small cell fragments essential for blood clotting, last only 5 to 7 days. Their rapid metabolic activity and susceptibility to bacterial growth contribute to this limited period. The differences in these durations reflect the varying cellular structures, metabolic rates, and sensitivities of each component to storage conditions, with cellular components generally having shorter shelf lives than plasma derivatives.
Fresh frozen plasma (FFP), the liquid portion of blood containing clotting factors and proteins, can be stored for up to one year or longer at very low temperatures. If stored below -60°C, FFP can last for up to seven years. Cryoprecipitate, rich in specific clotting factors like fibrinogen and Factor VIII, maintains viability for up to one year when frozen at -18°C or colder.
Factors Influencing Storage Duration
Specific storage durations for blood components are achieved through precise environmental controls and specialized solutions. Red blood cells are stored at 2°C to 6°C. This cold environment slows metabolic activity and minimizes bacterial growth, preserving oxygen-carrying capacity. Additive solutions, such as Saline Adenine Glucose Mannitol (SAGM) or CPDA-1, are mixed with red blood cells to provide nutrients and prevent clotting.
Platelets require storage at 20°C to 24°C with continuous gentle agitation. This agitation prevents clumping and helps maintain function. Storing platelets at colder temperatures can cause irreversible changes to their membranes, leading to rapid removal from circulation upon transfusion. Plasma and cryoprecipitate are stored frozen at -18°C or colder to preserve protein components and clotting factors. Rapid freezing within hours of collection is essential for fresh frozen plasma to maintain quality and efficacy.
Maintaining Safety and Quality
Ensuring the safety and quality of donated blood involves rigorous testing and strict adherence to protocols. All donated blood undergoes testing for infectious diseases (e.g., HIV, hepatitis) and blood type verification before transfusion. This comprehensive testing ensures the blood is safe for patient use. Blood banks maintain precise temperature control and continuous monitoring of storage units, with alarm systems to detect deviations.
Once a blood component reaches its shelf life, it is discarded and never used for patient transfusion. This prevents risks from decreased functionality or potential bacterial growth. While expired components are not used for patient care, some may be utilized for research or training. Adhering to these storage conditions and expiration dates ensures patient safety and effective, contaminant-free transfusions.