A colleague at a hospital in Minnesota reports that his laboratory currently stores antisera between -30 to -40 C. The laboratory is reassigning space and would like to replace the existing freezer with a smaller one. However, the smaller freezer only maintains temperatures as cold as -30 C. The inquiring colleagues asks if it is common practice for to store human antisera at -30 C or colder, or would the storage of the antisera in a standard -18 C to -30 C freezer (such as is used for FFP) sufficient?

The following comments have been received.

ADDENDA Feb. 19, 2007

1. According to Sandra Nance, MS, MT (ASCP) SBB, Director of Technical Services for the Penn-Jersey Region of the American Red Cross Blood Services, Director of the American Rare Donor Program and Director of IRL, Biomedical Services Operations and the The National Reference Laboratory for Blood Group Serology (NRLBGS) of American Red Cross Blood Services (attribution used with permission), antisera should always be stored according to manufacturer's instructions. If the antisera is not stored according to manufacturer's instructions, then it must be considered unlicensed. If the antisera is not commercial and/or is unlicensed (such as expired commercial antisera), then it should not be used to test or label units of blood unless the label indicates that the testing was performed using unlicensed reagents.

Sandy comments that "Assuming that the intent is to store a very rare unlicensed antisera for use at a later date, I have always opted for the coldest temperature possible, and in my laboratory it is -70C. So, storage at -70C , along with aliquoting the sample to avoid repeat or frequent thaw and re-freeze is my recommendation. I also have heard from others that the selection of a freezer that does not defrost is preferable."

2. Scott A. Brubaker, CTBS, Chief Policy Officer for the American Association of Tissue Banks (attribution used with permission) reports that according to Robert Stevenson, PhD (who has a long history at the ATCC and with cryobiology societies) the storage of human serum between -20 C to -30 C is acceptable for archiving up to 10 years. If longer storage times are contemplated, lower temperatures should be used. He adds that a good source of information would be the International Society for Biological Repositories (ISBER).

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