Blood Bank Guy Essentials Podcast 063CE: Anti-CD47 Testing Interference with Connie Westhoff
Feb 6, 2019
Connie Westhoff, researcher studying anti-CD47, discusses the interference this drug causes in blood bank testing. They explore the challenges in removing CD-47, the interference in ABO and antibody screening, and the use of polyethylene glycol absorption to remove interference. The importance of pretreatment ABO and RH typing, genotyping, and antigen match units are highlighted. The effects of anti-CD38 and potential interfering antibodies are also discussed.
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Anti-CD47 Causes Broad, Strong Reactivity
- Anti-CD47 causes strong, multi-phase reactivity including immediate-spin and 37°C reactions, invalidating reverse ABO typing.
- The antibody quantity can behave like an IgM in testing despite being IgG, producing widespread false positivity.
False-Negative DAT From Heavy Coating
- Anti-CD47 can produce a falsely negative DAT due to prozone/blocking while eluate is strongly positive.
- Massive coating of cells prevents antiglobulin reagents from binding, masking true positivity.
Use IgG4-Insensitive AHG Where Applicable
- Use a monoclonal anti-IgG AHG reagent that does not detect IgG4 to avoid detecting some anti-CD47 drugs (IgG4).
- Be aware this works only for specific IgG4-based anti-CD47 agents and not for all CD47 therapeutics.