Blood storage XXII. Improvement in red blood cell 2,3-DPG levels at six weeks by 20 mM PO4 in CPD-adenine-inosine

Inorganic phosphate has been known to assist red blood cell maintenance of ATP and in the presence of inosine to assist in the maintenance of 2,3-DPG. High concentrations of phosphate, while helping ATP maintenance, were found to be deleterious to 2,3-DPG maintenance in CPD- adenine preservatives. However, in the presence of inosine, concentrations of phosphate as high as 10 mM were advantageous to 2,3- DPG maintenance. The present study extends the observations on ATP and 2,3-DPG maintenance in CPD-adenine-inosine preservatives from the previous 10 mM to 20 mM phosphate. A high phosphate (20 mM) effect has been seen as improved maintenance of 2,3-DPG levels during the fifth and sixth weeks of storage of whole blood at 4C. This supports the previously reported observation of improved maintenance of 2,3-DPG in a 10 mM phosphate preservative. This is ten times the 2 mM phosphate concentration in CPD-adenine. In the low phosphate preservative (2 mM), 2,3-DPG maintenance is less than that in all of the higher phosphate preservatives after the second week of storage. ATP concentrations in this experiment show good maintenance throughout six weeks of storage.