Proper controls for EDTA/glycine-acid (EGA) treatment of direct antiglobulin test (DAT) positive red blood cells

A colleague has a question regarding controls for EDTA/glycine-acid (EGA) treatment of direct antiglobulin test (DAT) positive red blood cells. Currently they treat a Fy(a+b+), S+s+ cell along with the patient's red cells to show that the EGA treatment has not denatured these antigens. When calling some reference laboratories about their use of this reagent, none of them are doing using such a control practice. In addition, the manufacturer's instructions state that EGA treating the positive control cells can be omitted if the laboratory has previously confirmed that the relevant antigens are not destroyed by the treatment. They report having shown that these antigens are not denatured by the QC that they have done. Could a review of this QC be sufficient to stop EGA treating the positive control even if in the future different reagent red cells will be used as the control cells?

In response to the above question, the Scientific Director of a large immunohematology reference laboratory comments that the manufacturer's instructions should always be followed.

Submit comments to the e-Network Forum at enetworkforum@cbbsweb.org

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

W. Tait Stevens, MD
CBBS e-Network Forum Editor & Moderator

Elizabeth M. St. Lezin, MD
CBBS e-Network Forum Associate Editor & Moderator

The e-Network Forum is supported in part by the California Blood Bank Society (CBBS) and the American Red Cross Blood Services (ARCBS) and endorses collegial discussion among blood banking and transfusion medicine professionals. However, neither the CBBS nor the ARCBS in any way endorse the specific views and opinions expressed in the forum. The forum is not intended as a substitute for medical or legal advice and the content should not be relied upon for any medical or legal purposes. Readers should make their own determinations as to: (i) what constitutes appropriate medical, technical, and administrative practices, and (ii) how best to comply with laws and regulations relevant to their questions. For the latter, they should consider consulting, as to any medical matters, a qualified physician, and, as to any legal matters, an attorney familiar with related state and federal laws. The user of the forum, by accessing same, assumes all risks arising out of such use and releases CBBS and their respective members, directors, officers and agents from and against any loss, damage, claim or liability arising out of such use of the Forum.