A study published in TRANSFUSION has found that exposure of red cell units to 30 degrees Celsius for up to 60 minutes does not cause significant damage. These findings suggest that the widely implemented 30-minute rule, which restricts the time spent outside of controlled temperature environments, may be modified without sacrificing product quality or safety.
In an accompanying editorial, Dr. Alyssa Ziman described the study. Here is Dr. Ziman:
“Many blood bankers have questioned the validity of the 30-minute rule for reissuing blood. The origin of the 30-minute rule is based on studies performed more than 50 years ago that were limited in scope and evaluated a remarkably different red cell product than what is currently available.”
Current storage guidelines in the United States and Europe specify that storage temperatures may not exceed 6 degrees Celsius, and temperatures during transport may not rise above 10 degrees
Dr. Stephen Thomas and colleagues systematically exposed adult and pediatric units to 30 degrees Celsius once, twice, or three times for 30 or 60 minutes each on 3 separate days.
The researchers found no significant differences in hemolysis between adult units exposed to elevated temperatures for 1 period of 30 or 60 minutes and units not exposed. However, exposure to 30 degrees Celsius for 2 to 3 periods of 60 minutes was associated with increased hemolysis. Pediatric units were more sensitive to ambient temperature exposure. Supernatant potassium and ATP levels were also assessed, but bacterial growth was not evaluated.
Here is Dr. Thomas: “If studies of bacterial growth do not show cause for concern then an extension of the 30 minute rule could be considered. This would most likely result in a reduction in the number of blood components that are discarded.”
Based on the research team’s findings, replacing the 30-minute rule with a 60-minute rule may be appropriate. Once again, here is Dr. Ziman:
“These findings provide the catalyst to move forward with a new rule, which would still provide a safe and viable RBC component for transfusion and allow blood bankers to responsibly conserve this scarce resource.”
We’ll be back with another edition of Transfusion News on July 15th, and until then, thanks for joining us.