Red cell cryopreservation for serologic testing: bulk freezing with polyvinylpyrrolidone (PVP)

Area of Science:

• Transfusion Medicine
• Immunohematology
• Cryobiology

Background:

• Red cell cryopreservation is vital for immunohematology reference laboratories.
• Established methods include bulk freezing with glycerol and droplet freezing with polyvinylpyrrolidone (PVP).
• This study details a modified PVP bulk-freezing technique in a transfusion medicine setting.

Purpose of the Study:

• To evaluate a modified bulk freezing method for red blood cell cryopreservation using PVP.
• To assess the impact of agitation during incubation on red cell recovery.
• To determine optimal thawing temperatures for cryopreserved red cells.

Main Methods:

• Red blood cells were separated and incubated with PVP, with or without slow agitation.
• Cells were cryopreserved using a 1 mL bulk freezing method, differing from droplet freezing.
• Recovery rates were analyzed based on incubation agitation and thawing temperatures.

Main Results:

• The overall red cell recovery rate was 45% ± 9%.
• Slow agitation during incubation resulted in significantly higher recovery rates (47.9% ± 9.3%) compared to no agitation (42.3% ± 8.1%).
• Optimal thawing occurred at 37 °C, yielding a recovery rate of 46.6% ± 9.3%.

Conclusions:

• Modified bulk freezing with PVP achieved 45% red cell recovery.
• This method is suitable for cryopreservation and storage of large red cell volumes.
• The technique is advantageous when storage efficiency is prioritized over minimizing cell loss.