For those of you interested in a question about use of expired reagent panel cells, a blood banker who works at a hospital located Worcester, Massachusetts was wondering how other institutions handle the use of expired reagent panel cells. The laboratory at the inquiring blood banker's institution saves their expired reagent panel cells for use with the investigation of possible multiple antibodies or when rare cells are needed to rule out an antibody to a high frequency antigen. The inquiring blood banker wonders if there are regulations or guidelines regarding the use of expired reagent panel cells for the above mentioned purposes? She would also like to know what policy other blood banks are following for use of expired panel cells. Before sending the above question to the full network, the question was previewed by a blood banker familiar with the AABB Technical Manual who indicates that reagent red cells normally have an expiration that is set at 45 days after manufacturing of the reagent, but may be up to 66 days. According to this responding blood banker, it is common practice to use outdated panel red cells in the identification of antibody where in-date cells are inadequate for non-routine antibody identification. It is known that the reactivity of reagent red blood cells may diminish over time, and that the rate of diminishing reactivity is partially dependent upon the individual donor, the development of hemolysis or bacterial contamination of the reagent. In the experience of the responding blood banker, antigen stability is usually adequate for at least 2-3 weeks beyond the expiration outdate of reagent panel cells, provided they are refrigerated. However, many centers retain outdated panels for up to 2-3 months, or longer. When in doubt regarding antigen integrity of outdated reagent red cells, the responding blood banker emphasizes that it is prudent to run positive and negative controls of antigens in question. If specific typing anti-sera are unavailable, testing related antigens with anti-sera may allow for assessment of panel cell antigen integrity. Cells with particularly rare phenotypes are optimally stored frozen.

1. In the e-Network Forum Editor's opinion, if one uses expired reagents there should be approval to do so by an appropriate individual within the laboratory, a compelling justification to make such an exception, and clear documentation of the decision to vary from standard operating procedures.

2. In response to the above question and discussion, a blood banker submitted her hospital's SOP for using expired reagent panel cells, a copy of which is linked as a Word document. The e-network is invited to comment on the submitted SOP.

ADDENDA Feb. 27, 2002

3. According to Sheryl A. Kochman, Chief, Devices Review Branch of CBER/OBRR/DBA, (301-827-6123), some additional points to consider in using expired Reagent Red Blood Cells are as follows:

• Hemolysis is not the only indication of red cell deterioration.
• Reagent Red Blood Cells should also be examined for discoloration, usually turning varying shades of brown. This can be an indication of bacterial or chemical (e.g., enzyme byproducts of bacterial contamination, bleach) contamination and can lead to false positives or false negatives, even if you wash the cells.
• Reagent Red Blood Cells should also be examined for the presence of foreign matter, usually in the form of white clumps or "fuzz-balls" which are an indication of fungal contamination. Fungi love the sugar in the preservative solution and the antibiotics in the reagents are not very effective against fungi. Their presence can lead to false positive or negative results, even if you wash the cells.
• And even if the reagent appearance is acceptable, that does not mean that changes in the presence or strength of antigens have not occurred.

For all of the above reasons, the use of controls, both positive and negative, should be carefully considered. It should also be noted that freezing the cells does not make them "immortal." Controls should be used with frozen cells as well.

ADDENDA Feb. 28

4. An immunohematologist from Michigan does NOT recommend the use of outdated reagent (panel) RBCs in antibody identification studies. Rather, he is of the opinion that the ultimate test of compatibility in alloimmunized patients is the antiglobulin crossmatch, which is an AABB requirement. In the responding immunohematologist's opinion, to show that expired (or frozen) reagent RBCs react with reagent grade antisera and are therefore suitable for panel workups for exclusion purposes is nonsense! He adds that if you are unable to exclude an alloantibody to a common RBC antigen with in-date RBCs, it is perfectly OK to issue units that lack the corresponding antigen, provided the unit has not passed its outdate!

(Editor's note: The responding immunohematologist did not directly address the use of expired reagent red cells for the identification of an antibody to a high frequency antigen. However, he did say that he would occasionally use frozen RBCs that were acquired eons ago, presumably when attempting to identify or rule out such an antibody.)

ADDENDA Oct. 6, 2004

5. Readers are directed to the new discussion: Can expired panel cells be used in a manner that would be considered compliant?

Please submit comments to the e-Network Forum.

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