Skip to main content

Blood Bank

Whole Blood

While Whole Blood (WB) was the original product used for transfusion, its use for direct infusion has become relatively uncommon in most developed countries, largely replaced by component therapy. However, understanding Whole Blood is essential for historical context and because it remains the starting material for most blood components and still has niche applications, particularly in massive hemorrhage situations

What is Whole Blood?

  • Definition: Whole Blood is essentially blood as it is collected from the donor, containing all its primary constituents: Red Blood Cells (RBCs), Plasma, Platelets, and White Blood Cells (WBCs), suspended in an anticoagulant-preservative solution
  • Composition: A standard unit contains approximately:
    • ~450-500 mL of donor blood
    • ~63-70 mL of anticoagulant-preservative solution (e.g., CPD, CPDA-1)
    • Total Volume: ~513-570 mL
  • Key Point: It contains all components in roughly physiological proportions at the time of collection

Historical Context & The Shift to Component Therapy

  • Historically, WB was the only transfusion option available
  • The development of plastic bags with satellite containers and advances in centrifugation techniques allowed for the separation of WB into its constituent parts (RBCs, Platelets, Plasma, Cryoprecipitate)
  • Reasons for the Shift
    • Targeted Therapy: Allows clinicians to transfuse only the specific component the patient needs, avoiding unnecessary volume and constituents
    • Optimal Storage: Different components require different storage conditions for maximum viability and function (e.g., RBCs at 1-6°C, Platelets at 20-24°C, Plasma frozen)
    • Reduced Wastage: Prevents discarding functional components when only one part of the WB unit is needed
    • Concentration: Allows for concentrated doses (e.g., apheresis platelets, cryoprecipitate)
    • Reduced Adverse Reactions: Giving fewer unnecessary plasma proteins or WBCs can reduce allergic and febrile reactions

Preparation (Collection)

  • Collected via standard venipuncture into a primary collection bag containing anticoagulant-preservative solution (CPD, CPDA-1)
  • Crucial Distinction: While most blood donations start as Whole Blood collection, the vast majority are processed into components within hours. Units intended for transfusion as Whole Blood are specifically designated and stored as such

Indications for Transfusion

The use of Whole Blood for direct transfusion is now limited primarily to:

  • Massive Hemorrhage / Trauma Resuscitation: Especially in military settings or trauma centers adopting “balanced resuscitation” strategies. The rationale is to replace lost blood with a product containing oxygen-carrying capacity (RBCs), volume and clotting factors (plasma), and some platelets, potentially closer to physiological ratios than combining separate components. Often, “fresh” whole blood (collected <24 hours prior) is desired in these settings to maximize platelet and factor function, though this presents significant logistical challenges
  • Neonatal Exchange Transfusion: Sometimes used, though often reconstituted WB (RBCs + FFP) or RBCs alone are used
  • Resource-Limited Settings: May be used more commonly where the capacity for component preparation is limited

Storage and Expiration

This is a key limitation of Whole Blood:

  • Storage Temperature: 1°C to 6°C (same as RBCs)
  • Expiration: Determined by the anticoagulant-preservative solution:
    • CPD or CP2D: 21 days
    • CPDA-1: 35 days
  • Critical Limitations due to Storage Temperature
    • Platelet Function: Platelets rapidly lose viability and function when stored at 1-6°C. After 24-48 hours, stored WB contains very few functional platelets
    • Labile Coagulation Factors: Factors V and VIII degrade significantly at refrigerated temperatures over time. Stored WB is a poor source of these factors compared to FFP
    • WBC Viability: Leukocytes also lose function, though their presence contributes to risks like alloimmunization and FNHTRs

Advantages (in Specific Contexts)

  • Balanced Resuscitation: In massive hemorrhage, potentially provides a more physiologically balanced replacement fluid compared to crystalloids or just RBCs initially
  • Logistical Simplicity: One product to store and transfuse instead of coordinating three (RBCs, plasma, platelets) – relevant in emergencies or remote settings
  • Reduced Donor Exposure (Potentially): Receiving one WB unit exposes the recipient to one donor, whereas receiving individual components might involve multiple donors (though apheresis components mitigate this)

Disadvantages (Why Component Therapy is Preferred)

  • Suboptimal Component Viability: Platelets and labile factors (V, VIII) are poorly preserved at 1-6°C
  • Component Wastage: Transfusing unnecessary components (e.g., giving plasma and non-functional platelets to a patient who only needs RBCs)
  • Circulatory Overload Risk: Larger infusion volume compared to packed RBCs, potentially problematic for patients sensitive to volume (e.g., cardiac or renal patients)
  • Increased Risk of Certain Reactions: Contains more plasma proteins (higher risk of allergic reactions) and non-functional leukocytes (higher risk of FNHTRs, alloimmunization, CMV transmission) compared to leukoreduced, plasma-reduced components
  • Storage Incompatibility: No single temperature optimally preserves all components simultaneously

Modifications

  • Leukoreduction: Whole Blood can be leukoreduced using appropriate filters, though this is less common than LR for components
  • Irradiation: Can be irradiated for the same indications as RBCs/Platelets (preventing TA-GVHD). Irradiation imposes the same expiration constraint (original outdate or 28 days post-irradiation, whichever is sooner)

Administration

  • Compatibility: MUST be ABO identical with the recipient. This means the donor’s red cells must be compatible with the recipient’s plasma, and the donor’s plasma must be compatible with the recipient’s red cells. Rh compatibility is also required
  • Crossmatch: A crossmatch is required before transfusion
  • Filtration: Administered through a standard blood filter (170-260 microns)
  • Infusion Time: Must be completed within 4 hours of removal from controlled storage

Potential Risks / Adverse Reactions

Includes the risks associated with all components:

  • Hemolytic Transfusion Reactions (Acute and Delayed)
  • Febrile Non-Hemolytic Transfusion Reactions (FNHTRs)
  • Allergic Reactions (Mild to Anaphylaxis)
  • Transfusion-Associated Circulatory Overload (TACO)
  • Transfusion-Related Acute Lung Injury (TRALI)
  • Septic Reactions (Bacterial Contamination)
  • Alloimmunization (RBC, HLA, Platelet antigens)
  • Disease Transmission
  • TA-GVHD (if not irradiated when indicated)

Key Terms

  • Component Therapy: The practice of transfusing specific blood components (RBCs, Platelets, Plasma) rather than Whole Blood
  • Anticoagulant-Preservative Solution: Solutions like CPD, CPDA-1 used in collection bags
  • Massive Hemorrhage: Acute, severe blood loss requiring large-volume transfusion
  • Balanced Resuscitation: Transfusion strategy aiming to replace lost blood with components (or WB) in a ratio approximating physiological levels
  • Labile Factors: Coagulation Factors V and VIII, which degrade relatively quickly at refrigerated temperatures
  • ABO Identical: Donor and recipient have the same ABO group (required for WB transfusion)