Vol. 14 Issue 12
Q & A
How Long Can Blood Remain at Room Temperature?
Q: I am currently working with our nursing team to come up with new blood bank policies and procedures. Currently, we have a policy that states that a unit of blood cannot be returned to controlled storage once it has been out of the controlled refrigerator for 30 minutes. How long can blood remain at room temperature before the transfusion is started?
A: The 30-minute policy seems to be a standard worldwide policy and is really a practical compromise between necessary transport arrangements across a hospital site and minimizing increases in temperature. Obviously, the greater the temperature increase and time at the higher temperature, the greater the risk of bacterial proliferation.
Very little has been published on this subject, yet most hospitals seem to have agreed independently on this standard. Some experts quote a 9C or 10C maximum temperature that a blood pack can reach during transport–this is the approximate temperature a unit will reach in 30 minutes if transported carefully.
I did some work on this topic a number of years ago and found that the core blood bag temperature could rise to between .9.5C and 23.5C after 30 minutes, depending on how the unit was handled during this time. Hand-held and constantly agitated blood obviously produced the greatest temperature increase. We did consider issuing all our units in polystyrene "burger boxes" to help maintain temperature, but as we issue over 900 units per week, this would have been a major problem in itself.
As a follow-up, we carried out another survey where we attached "chill checkers" to about 200 units of blood. These devices permanently changed color if its target temperature was reached. A 17C bag surface temperature is equivalent to a core temperature of 9C. These units were preferentially selected for patients who were unlikely to be transfused during the first three weeks of storage. This meant that they did more journeys to and from theatres than normal units. We only had one unit whose chill checker changed color and that was a unit that had been transferred out of the hospital with the patient and without our knowledge. This did reassure us that our system was relatively safe.
We had a long debate about how long a unit should be out of the refrigerator before putting up the unit. As with other correspondents, some of our staff felt that if transfusion should be completed within five hours, what difference did it make if it sat on the ward or hanging from a drip stand during this time. The prevailing view, however, was that if the unit was left waiting at the nurses station for any length of time, then there was much more chance that it would be temporarily placed in a dangerous environment.
We felt that we should impose some rule that minimized the chances of this happening, but at the same time allowing for the occasional delay in putting up a unit due to a crisis on the ward, for instance. We settled for one hour. We do now have the benefit of having an electronic blood tracking system that controls access to the blood refrigerators.
We are slightly out of step with the five-hour limit for a transfusion to be completed. This was an original National Blood Service guideline (Handbook of Transfusion Medicine), which we adhered to. All of our internal hospital guideline booklets contain this recommendation. However, the last edition of this book reduced this time to four hours and we will change when we republish our own guidelines in the near future.
A: The policy at our facility is that the infusion must be started within 30 minutes once it leaves the transfusion service. We do not place units back in inventory if they are returned after 30 minutes. We also have a four-hour transfusion time limit for the unit to be infused.
The AABB Technical Manual, 13th Edition, Chapter 22, page 491, states, "If the transfusion cannot be initiated within 30 minutes, the blood should be returned to the blood bank for proper storage. It should not be left at room temperature or stored in an unmonitored refrigerator."
Teresa Eskridg, MT(ASCP)
A: There are several answers, depending on the situation. When dispensing blood for transfusion, the rule is 30 minutes at room temperature if the blood is to be returned to inventory. The basis for this rule is research many years ago showing that blood reached 10C after about 45 minutes at room temperature. For shipping, blood is not to exceed 10C. Thirty minutes was selected to assure blood stayed below 10C, even under severe conditions.
For freshly collected whole blood, the blood is to be cooled towards room temperature and platelets separated within eight hours of collection. The metabolism rate of red blood cells is dependent on the storage temperature, with the rate of metabolism slowing as the temperature of storage is lowered. However, a few hours at room temperature, or at 10C, is not detrimental to the preservation of the red cells for the full storage time to expiration date. The expiration date is based on the specific anticoagulant/preservative solution used.
For transfusion, the rule is four hours from the time dispensed from the transfusion service. This rule has scientific basis. When transfusing, the blood is in an "open" system, in that the hermetic seal has been broken. Based on growth rates of bacteria, four hours was selected as a safe interval, even if the blood was contaminated during inserting the transfusion set cannula into the blood bag port. Four hours is also used for pooled platelets and pooled cryoprecipitate, again an "open" system.
Melanie S. Kennedy, MD
This Week's Q & A Panel
Dave Doolan is chief biomedical scientist, Blood Transfusion Department, St. James Hospitals, Leeds, UK.
Teresa Eskridge is Blood Bank supervisor at McLeod Regional Medical Center, Florence, SC.
Dr. Melanie S. Kennedy is director of Transfusion Medicine, The Ohio State University Medical Center and associate professor of Pathology and Allied Medical Professions College of Medicine and Public Health, The Ohio State University, Columbus.
To volunteer as a panelist for Q&A, please contact Daniella King at email@example.com or 800-355-5627, ext. 1225.