The development of flexible plastic blood bags has permitted effective blood component production and therapy. However, the plasticizer di(2-ethylhexyl)phthalate (DEHP), whose toxicity in humans is still undefined, is known to leach from the plastic into stored blood. Despite the availability of bags made of plastics not using DEHP, the collection and storage of red cells is still done in DEHP plasticized packs, and in fact the storage life for red cells has recently been increased up to 49 days using new anticoagulant-preservative solutions. We examined the relationship between DEHP and stored red cells. We found that 28 percent of available 14C-DEHP binds immediately to sites in both the membrane and cytosol fractions of the red cells, and that the total amount and distribution of 14C-DEHP does not change significantly over 7 days. When red cell concentrates were stored with or without DEHP, using either plastic (polyolefin) bags not containing DEHP or glass, definite reduction in the osmotic stability of the red cells was found in the absence of DEHP. Plasma-free hemoglobin levels were 90.3 mg per dl after 35 days of storage in plastic packs containing DEHP and 181.7 mg per dl in the polyolefin bags. The advantages of improved in vitro stability of red cells stored in plastics containing DEHP must be weighed against the potential hazards of patient exposure to DEHP.

Currently, platelet concentrates are stored in 50 to 60 ml of plasma. A major drawback to storage in plasma is the considerable loss of platelet function which occurs during storage. A modified Tyrodes medium has been developed for storage of platelets. A comparison between platelet concentrates stored in this medium and in plasma showed that platelet aggregation and release responses to synergistic pairs of stimuli were equivalent for both types of concentrates on the day of preparation and after 72 hours. Platelet aggregation and release responses to single stimuli, the content of membrane glycoproteins, and the pH declined during storage but were similar for both preparations. The data show that plasma is not required to maintain in vitro platelet function during storage of platelet concentrates, but in vivo functions remain to be determined. The use of an artificial medium has the advantages of decreasing patient exposure to plasma contaminants, generating additional plasma for fractionation, and controlling more exactly the storage environment.

The accumulation of the plasticizer di-2-ethylhexylphthalate (DEHP) in blood and blood components has been of considerable concern for some time. We have followed the accumulation of DEHP and one of its major metabolities, mono-2-ethylhexylphthalate (MEHP) during storage of whole blood, platelet-rich plasma, platelet concentrates, and platelet-poor plasma for periods ranging from 72 hours to four weeks. Both phthalates showed a progressive increase in concentration with time. While the levels of DEHP were much greater than those of MEHP, there was nonetheless a significant and continual increase in MEHP in all preparations. The highest concentrations of both DEHP and MEHP were found in the platelet-poor plasma, indicating that platelets do not have a major role in the accumulation of the phthalates in blood. The accumulation of MEHP was shown to be a direct result of the metabolism of DEHP by plasma protein(s) rather than leaching from the blood bag.

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