Cryopreservation of human platelets with 1.4 m glycerol at -75 degrees C in PVC blood packs.

We have previously described a laboratory technique for the cryopreservation of human platelets with 1.4 molar glycerol. For the present study we adapted that method for use in clinical blood banks, and we describe the results of in vitro assays of platelets preserved in PVC packs, with storage at -75 degrees C for 1 month. The results suggested that substitution of the PVC pack for standard, 4 ml polypropylene freezing vials had little effect, but substitution of processing (addition and subsequent removal of glycerol) in PVC packs for processing in polystyrene containers resulted in a marked reduction in recovery. The final results, where the entire process was carried out in PVC packs was not satisfactory; only approximately 50% of the platelets were recovered and they exhibited only approximately 30% hypotonic stress response and approximately 3% aggregation response to ADP. We conclude that -75 degrees C may be too high a storage temperature, or that the specific blood packs that we used may be unsuitable for this process, or both.