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Blood Bank

Apheresis Products

Apheresis Products represent components collected using a specialized technology that allows for the selective removal of one or more specific blood components from a donor, while returning the remaining constituents to their circulation. This contrasts with whole blood donation, where all components are collected initially and then separated later in the laboratory

What is Apheresis (Hemapheresis)?

  • Definition: Derived from the Greek word meaning “to take away” or “separate,” apheresis is an automated process where:
    1. Whole blood is withdrawn from a donor (or patient, in therapeutic apheresis)
    2. The blood is anticoagulated, usually with citrate
    3. It enters a sterile, disposable tubing set within an apheresis machine
    4. The machine uses centrifugation (or sometimes filtration) to separate the blood into its different components based on density (RBCs heaviest, then granulocytes, lymphocytes, platelets, plasma lightest)
    5. The desired component(s) are selectively diverted into a collection bag
    6. The remaining components are recombined and returned to the donor/patient through the same or a different venous access point
  • Key Feature: Allows for the collection of a larger quantity of a specific component from a single individual compared to what can be derived from one unit of whole blood donation

Common Apheresis Products for Transfusion

  • Platelets (Plateletpheresis / Single Donor Platelets - SDP)
    • What’s Collected: A concentrated dose of platelets, suspended in a small amount of plasma or a mixture of plasma and Platelet Additive Solution (PAS)
    • Key Advantage: One apheresis platelet unit contains a full therapeutic dose for an adult (typically ≥ 3.0 x 10¹¹ platelets), equivalent to pooling 4-6 units of Whole Blood Derived (WBD) platelets. This reduces recipient exposure to multiple donors, minimizing risks of alloimmunization and disease transmission
    • Donor Considerations: Donors can typically donate platelets more frequently than whole blood (e.g., every 7 days, up to 24 times/year)
    • Storage: Standard platelet storage (20-24°C with continuous agitation, 5-7 day expiration)
    • Leukoreduction: Usually inherently leukoreduced by the collection process
  • Plasma (Plasmapheresis)
    • What’s Collected: Plasma, intended either for transfusion (as FFP, PF24) or for further manufacturing (“Source Plasma”) into plasma derivatives (Albumin, IVIG, factor concentrates)
    • Key Advantage: Collects a larger volume of plasma (~500-880 mL, depending on donor weight and procedure) than can be obtained from a single whole blood donation. Efficient way to collect plasma for specific needs
    • Donor Considerations: Frequency depends on the product type (less frequent for FFP, more frequent for Source Plasma under specific programs)
    • Storage (Transfusion Plasma): Standard frozen storage (≤ -18°C, 1 year expiration)
  • Red Blood Cells (Erythrocytapheresis / Red Cell Apheresis)
    • What’s Collected: Primarily Red Blood Cells. Most commonly performed as a “Double Red Cell” (2RBC) donation
    • Key Advantage: Collects two standard doses of RBCs from a single donor in one session. Efficient for donors and helps manage inventory
    • Donor Considerations: Requires donors to meet higher hemoglobin/hematocrit levels and often height/weight criteria to ensure they have sufficient blood volume. Donation interval is longer than whole blood (typically 112 days / 16 weeks)
    • Storage: Standard RBC storage (1-6°C, 42 days with additive solution)
    • Leukoreduction: Often inherently leukoreduced
  • Granulocytes (Granulocytapheresis)
    • What’s Collected: A concentrate rich in neutrophils
    • Key Advantage: Apheresis is essentially the only practical way to collect a therapeutic dose of granulocytes
    • Donor Considerations: Requires donor stimulation with G-CSF and/or corticosteroids to boost neutrophil counts. Donation is infrequent and targeted for specific patient needs
    • Storage: Unique (20-24°C, no agitation, 24-hour expiration). Must be irradiated and crossmatched
  • Hematopoietic Progenitor Cells (HPCs) / Stem Cells (Leukapheresis)
    • What’s Collected: Mononuclear cells containing hematopoietic stem cells, used for transplantation
    • Key Advantage: Apheresis collection of Peripheral Blood Stem Cells (PBSCs) is now the most common method for HPC donation (vs. bone marrow harvest)
    • Donor Considerations: Requires donor mobilization with G-CSF for several days prior to collection to push stem cells from the marrow into the peripheral blood. Requires careful HLA matching between donor and recipient (unless autologous)
    • Storage: Often cryopreserved for later use
  • Multicomponent Collection
    • What’s Collected: Two or more different components during a single apheresis procedure (e.g., platelets and plasma; platelets and red cells; plasma and red cells)
    • Key Advantage: Maximizes the yield from a single donor visit and venipuncture

Advantages of Apheresis Collection (General)

  • Reduced Donor Exposure: Fewer donors needed to achieve a therapeutic dose (especially for platelets), reducing risks for the recipient
  • Higher Yield: Larger volume/dose of the target component collected
  • Component Specificity: Collects only the needed component(s)
  • Donation Frequency: Allows donors to give certain components (platelets, plasma) more often than whole blood
  • Leukoreduction: Many apheresis procedures inherently produce leukoreduced components

Disadvantages / Considerations of Apheresis

  • Donor Time Commitment: Procedures take longer than whole blood donation (typically 1-2 hours)
  • Citrate Reaction: The anticoagulant (citrate) is returned to the donor, potentially causing temporary hypocalcemia symptoms (tingling, chills). Requires careful monitoring and management (e.g., oral calcium)
  • Venous Access: Often requires good veins, sometimes in both arms
  • Cost: Apheresis machines and disposable kits are more expensive than whole blood collection supplies
  • Trained Personnel: Requires staff specifically trained in operating apheresis equipment and managing donors

Regulatory and Quality Aspects

  • Apheresis devices are regulated by the FDA
  • Procedures must be validated
  • Collected components must meet specific quality control standards (e.g., platelet count, volume, residual WBCs, pH)

Key Terms

  • Apheresis (Hemapheresis): Automated process to separate and collect specific blood components while returning others to the donor
  • Citrate: Anticoagulant used in apheresis; binds calcium
  • Citrate Reaction: Symptoms (tingling, chills) due to temporary low ionized calcium from returned citrate
  • Plateletpheresis: Apheresis collection of platelets (yields Single Donor Platelets - SDP)
  • Plasmapheresis: Apheresis collection of plasma
  • Erythrocytapheresis: Apheresis collection of red blood cells (often Double Red Cell - 2RBC)
  • Granulocytapheresis: Apheresis collection of granulocytes
  • Leukapheresis: Apheresis collection of leukocytes (often referring to HPC/stem cell collection)
  • Mobilization/Stimulation: Use of agents like G-CSF or steroids to increase the count of specific cells (neutrophils, stem cells) in the donor’s blood before apheresis