An e-Network member asked a question regarding the freezing of red cell units. After comparing the AABB Standards against the AABB Technical Manual, this blood banker noticed a conflict, specifically, Standard 5.7.5.2 states that "red cells shall be frozen within 6 days of collection, except when rejuvenated" while the Technical Manual states that "ordinarily, red cells are glycerolized and frozen within 6 days of collection or rejuvenated and frozen up to 3 days after they expire, but RBCs preserved in AS-1, AS-2, and AS-5 can be frozen up to 42 days with adequate recovery." According to this blood banker, the current AABB Standards do NOT appear to give this concession as it does not differentiate between CPDA-1 and AS units. Rejuvenated AS-1 units have an expiration date of 3 years instead of 10 years and Cytosol is not licensed for AS-3 and AS-5. The inquiring member works at an institution that serves as a rare donor depot, but her center no longer draws its own donors. Rather, her center freezes units received from a supplier. Most of the units are preserved in AS and are older than 6 days. They have been freezing these units without rejuvenation, but now she realizes that the Standards do not give this option. This blood banker wants to know if there is any information regarding this apparent discrepancy? Do other institutions have the same problem and if so, how are they resolving it?

The above question was discussed directly with Ginny Tyler, President of the California Blood Bank Society, editor of the current AABB Technical Manual, and member of the AABB Standards Committee.

Here is her summary of the facts:

This issue has been discussed by the AABB Standards committee, which realizes that there is a discrepancy between the Standards and the Technical Manual. The pat answer when there is a conflict between the Standards and the Technical Manual is that the Standards represent what we are expected to do. The Technical Manual serves as a tool or a guidance, but does not have the authority of the standards. The Technical Manual offers additional information and supportive documentation. Since the publication period of the Technical Manual differs from the Standards, there will be times when the Standards have changed and the two documents will be out of "alignment". Having said that, the Standard 5.7.5.2 does not offer any leeway for changes in manufacturer instructions or new licensure with the FDA. The Technical Manual addressed the other options to freezing red cells based on manufacturer instructions, new FDA licensure, and common practice. A search of the literature performed by Dr. Mark Brecher revealed that in 1986, Button et al reported a 24 hour survival of erythrocytes that had been stored for 42 days in AS-1, rejuvenated, frozen, thawed, and then reinfused into the donor to be 83.8% for five donors studied, and 78.2% for six controls whose units had not been rejuvenated. [Ref: Button L, Kruskall MS, Scanlan A, Kevy S. Rejuvenation of red cells drawn in ADSOL to extend autologous red cell storage. Transfusion 1986;28:558 abstract]. In 1989 Rathbun et al reported that units from 9 donors that were stored in AS-3 for 42 days, frozen (but not rejuvenated), thawed and then reinfused into the donors gave indices of therapeutic effectiveness greater than 60%. (Ref. Rathbun EJ. Nelson EJ. Davey RJ.;Posttransfusion survival of red cells frozen for 8 weeks after 42-day liquid storage in AS-3. Transfusion. 29(3):213-7, 1989 Mar-Apr.). These authors concluded that erythrocytes stored in AS-3 could be frozen at any time up to their 42-day expiration without the need for rejuvenation. The Standards committee attempted to see if any AABB Reference lab had data regarding the freezing of rare units without rejuvenation after 6 days of storage, but none could provide any data on post transfusion red cell survival. Since in today's climate of Institutional Review Boards etc., it is not expected that any trials will be forthcoming, therefore the Standards Committee had to accept the older references.

Given the available information, the Standards committee revised this standard for the 21st edition, which is proposed to read as follows:

5.7.5.2:
Red Blood Cells processed WITHOUT an additive solution shall be frozen within 6 days of collection, EXCEPT when rejuvenated.

5.7.5.2.1
RBCs processed WITH an additive solution shall be frozen prior to the expiration date of the RBC. (This will permit freezing of AS red cell units without the need for rejuvenation).

5.7.5.2.2
The RBCs processed for freezing shall be placed in the freezer within 6 hours of opening the system.

If you have additional data to assist the AABB Standards Committee on this issue, please submit it, ASAP.

Please submit comments to the e-Network Forum.

Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator