Preparation of Washed Packed Red Blood Cells

• Washing red blood cells is performed to remove unwanted plasma proteins, including antibodies that might interfere in reactions
• Washing process involves suspending whole blood with normal saline solution, mixing, centrifuging, and decanting the supernatant fluid
• Some red cells are lost during the washing process
• Indications for using washed RBCs include:

  • Patients with a history of severe allergic reactions (anaphylactic or urticarial)
  • Patients with IgA deficiency and documented anti-IgA antibodies
  • Patients with recurrent febrile transfusion reactions not prevented by leukocyte reduction
  • Neonates or fetus patients with renal failure before transfusion of potassium-depleted units
• Materials & Equipment needed for washing red blood cells:

  • Graduated conical tubes with screw cap cover (10ml capacity)
  • Gloves
  • Marking pen
  • Gum label
  • Centrifuge (set at 3400 rpm)
  • Pasteur pipette
  • Test tube rack
• Reagents/Samples required:

  • Normal saline solutions (0.85% - 0.9% NaCl) in a wash bottle
  • Whole Blood
• Pre-Laboratory Procedures:

  • Wear PPEs
  • Prepare workstation with all necessary materials, equipment, reagents, supplies, and waste bin/container nearby
  • Label tubes as Washed Red Blood Cells using gum label
  • Perform blood extraction and collect blood to fill EDTA tubes, preferably 5 tubes with properly identified phenotype (A Positive, B Positive, O Positive)
• Procedures for washing red blood cells:

  1. Dispense 0.5 ml of whole blood into a centrifuge tube

  2. Add NSS until the mixture reaches 5ml, cover the tube

  3. Mix by gentle inversion 3 to 5 times

  4. Centrifuge the sample for 2 minutes at 3,400 rpm

  5. Pipette and discard the supernatant into a waste bottle, ensuring packed red cells are not disturbed

  6. Repeat steps 2-5 three to four times
• Post-Laboratory Procedures:

  • Set aside washed red blood cells for the next activity
  • Dispose of waste generated in the laboratory procedures in the waste bin/container
  • Replace gloves if heavily soiled during the lab exercise