Which precautions are required when antigen phenotyping CDP-treated red cells?

Red cells with a positive DAT present problems when antigen phenotyped by indirect antiglobulin test (IAT). One solution is to render the cells DAT-negative by treatment with chloroquine diphosphate (CDP). Precautions include:

  • Using anti-IgG for IAT phenotyping, since CDP does not remove complement.
  • Including an inert control of the CDP-treated patient's cells to control for non-specific agglutination after incubation (e.g., inert AB serum + treated cells carried through IAT).
  • Including CDP-treated panel cells as positive and negative antisera controls.