Whole Blood Classification
Whole blood is both a blood component AND can serve as the source material from which other blood components are derived—the terminology depends on the clinical and regulatory context.
Regulatory and Clinical Framework
Whole Blood as a Component
- Whole blood is classified as a blood component when used directly for transfusion, containing all cellular elements (red cells, white cells, platelets) and plasma in their natural proportions 1.
- The FDA and blood banking standards treat whole blood as a distinct transfusable component, requiring the same testing, typing, and labeling as other blood products 1.
- Modern transfusion medicine has largely replaced whole blood with component therapy (separated red cells, platelets, plasma), but whole blood remains a recognized therapeutic component, particularly for massive hemorrhage 2, 3.
Whole Blood as Source Material
- Whole blood simultaneously serves as the starting material from which blood components are manufactured through centrifugation and separation processes 1.
- Platelet concentrates are prepared by centrifugation of standard units of whole blood using either the platelet-rich plasma (PRP) method or buffy coat (BC) method 1.
- The BC method involves high-speed centrifugation of 450 mL whole blood donations to collect 40-50 mL buffy coats at the red cell/plasma interface 1.
- Component separation maximizes utility by allowing different storage conditions for each product: red cells at 4°C for up to 3 weeks, platelets at 22°C for up to 5 days, and plasma frozen at -25°C 4, 5.
Clinical Context Matters
When Whole Blood Functions as a Component
- Low titer group O whole blood (LTOWB) is increasingly used as a primary resuscitation component for massively bleeding trauma patients, providing concentrated hemostatic function superior to reconstituted components 2, 3.
- Whole blood can be stored under refrigeration for up to 35 days while retaining acceptable hemostatic function 3.
- Fresh whole blood from walking blood banks serves as an emergency component when stored products are unavailable 3.
When Whole Blood Functions as Source Material
- In blood banking operations, whole blood donations are routinely processed into components rather than transfused intact, allowing optimal storage and targeted therapy 4, 6, 5.
- Blood component therapy supplanted whole blood transfusion in industrialized countries in the mid-twentieth century and remains standard care for most patients 6.
Key Distinction
The critical distinction is functional, not categorical: Whole blood is a blood component by definition (it is a part of the blood supply used for transfusion), but it also serves as the raw material from which other components are manufactured. The term "blood product" is often used more broadly to encompass both whole blood and its derivatives 4, 6, 5.