In vivo and in vitro comparison of platelets stored in either synthetic media or plasma.

Since 1980, several synthetic media have been developed for the storage of platelets for transfusion. At present, platelets suspended in approximately 70% synthetic medium and 30% plasma can be stored for at least 5 days at very stable pH levels, generally pH 6.8-7.2. Present knowledge suggests that synthetic media should contain at least acetate, citrate, phosphate, potassium and magnesium. Future studies will probably result in the inclusion of other components to this list. Glucose for platelet metabolism will generally be supplied by carryover of plasma from the original platelet preparation. In addition, improved plastic containers for the storage of platelets will probably facilitate the introduction of new synthetic media. In six studies comparing synthetic media with plasma as the storage environment, and involving patients with intensive chemotherapy for haematological malignancies, the clinical outcome in terms of corrected count increments (CCI) generally indicated similar results. Three studies suggested significant reduction of the incidence of transfusion reactions of platelets suspended in synthetic media as compared with plasma. For future comparisons of platelet storage in either plasma or new synthetic media, additional platelet survival and recovery studies, as well as patient-transfusion studies, will be needed as in vitro data may not always reflect the clinical outcome. This will add further knowledge to data from the present few clinical studies available that compare storage of platelets in either synthetic media or plasma.