A comparative study showing the potency of anti-C3d and anti-immunoglobulin G in polyspecific anti-human globulin using fresh and cryopreserved red blood cells.

BACKGROUND: The antiglobulin test is used to determine red blood cells (RBCs) having surface-bound immunoglobulin G (IgG) and/or complement (C3b, C3d, C4b, and C4d) free in serum or attached to antigens on RBCs. In such circumstances, the quality of the anti-human globulin (AHG) which is used in routine cross-match/indirect agglutination test plays a vital role in blood transfusion medicine. For potency testing of polyspecific AHG, it is recommended by the Food and Drug Administration and the Centre for Biologics Evaluation and Research to use fresh O +ve RBCs within 1 hr of collection for sensitization with anti-C3d.

AIM AND OBJECTIVE: Freshly collected red cells were cryopreserved and stored at a temperature of -70°C for 30 days. These cells were then sensitized with C3d and IgG after deglycerolization. Their viability was checked by potency testing using polyspecific AHG-containing anti-C3d and anti-IgG.

MATERIALS AND METHODS: Anonymous left over fresh whole blood samples were collected from the Indian Red Cross Society, New Delhi, with CPDA as an anticoagulant, and the samples were treated within 1 h of collection. ABO and Rh (D) phenotyping was performed by test tube method. RBCs and plasma from the same donor were used throughout the study.

RESULTS: In this comparative study, fresh RBCs (O +ve) maintained their viability after cryopreservation and were also found to be suitable for sensitization with C3d and IgG. The potency of polyclonal AHG did not differ significantly with fresh RBCs and cryopreserved RBCs for 30 days.

CONCLUSION: This result suggests that the sensitization of fresh RBCs with IgG and C3d is not affected by using cryopreserved cells for 30 days.