Effect of 6-hour exposure to 20 degrees C on the ATP content and other biochemical measures of CPDA-1 packed red cells.

Blood donations for clinical use are routinely stored at 2 degrees C to 6 degrees C for 35 to 42 days. It is common practice for RBCs exposed to temperatures above 10 degrees C to be destroyed, although the American Association of Blood Banks Technical Manual states "Blood exposed to temperatures above 10 degrees C is not necessarily unsuitable for transfusion". To clarify this issue we investigated the effect of 6-hour storage at 20 degrees C on the content of ATP and other biochemical measures of CPDA-1 packed red cells. CPDA-1 packed RBC units were exposed once at day 5 (group 1), day 15 (group 2) or day 30 (group 3) of their shelf life to 20 degrees C for 6 hours. Control groups were continuously refrigerated. Under all conditions of storage, the ATP concentrations decreased with time. Initial ATP levels of five-day old CPDA-1 packed RBCs were 3.94 mumol/g Hb in the test group and 3.73 mumol/g Hb in the control group. At day 30 after warming (day 35 of the shelf-life) the ATP concentrations declined to 2.78 mumol/g Hb (test group) and to 3.55 mumol/gHb (controls). In the test series which were warmed at day 15 and day 30 of shelf-life the ATP levels declined to 3.16 mumol ATP/g Hb and 2.92 mumol ATP/g Hb at day 35 of shelf-life. There was no significant difference between test and control group with respect to the lactate levels, whole-blood glucose, sodium and potassium. The percentage of hemolysis was lower than 0.5% under all conditions of storage. Our data show that a shorter period of moderate warming (6h, 20 degrees C) does not lead to a critical decline of ATP and glucose concentrations in CPDA-1 packed RBCs. The survival of RBCs stored in CPDA-1 is most highly correlated with maintaining ATP concentrations above a value of about 2 mumol per g of Hb [3]. The ATP levels in our study were well above this threshold.