EDTA/glycine-acid versus chloroquine diphosphate treatment for stripping Bg antigens from red blood cells

EDTA/glycine-acid (EGA) has been reported to remove IgG-bound antibodies from red blood cells (RBCs) and to denature Kell system and Era antigens. EGA-treated RBCs were tested in parallel with chloroquine diphosphate (CDP)-treated RBCs to evaluate whether EGA would remove Bg antigens from RBCs as efficiently as CDP. Fifty-seven serum/plasma samples containing known Bg antibodies were tested with untreated Bg+ RBCs, EGA-treated Bg+ RBCs, and CDP-treated Bg+ RBCs by an indirect antiglobulin test (IAT), using a low-ionic-strength additive solution and murine monoclonal polyspecific antiglobulin reagent. Of 57 samples, 40 (22 anti-Bga, 17 anti-Bgb, and 1 Bg-related) were nonreactive by IAT with EGA-treated RBCs and CDP-treated RBCs, 14 (7 anti-Bga, 4 anti-Bgb, and 3 Bg-related) were nonreactive by IAT only with EGA-treated RBCs, none were nonreactive in IAT with only CDP-treated RBCs, and 3 (anti-Bga) were still reactive by IAT with EGA-treated RBCs and CDP-treated RBCs. Therefore, EGA strips Bg antigens from RBCs. Our results indicate EGA treatment is more efficient and requires less time (1-2 minutes) to perform than the CDP procedure (30-120 minutes) for removal of Bg antigens from RBCs.