Why were K and Jka phenotyping done using monoclonal anti-K and CDP-treated red cells, respectively?

K typing was done using monoclonal (IgM) anti-K because the patient has a positive DAT and typing by antiglobulin test is contraindicated unless the cells are first rendered DAT-negative.

Because monoclonal IgM anti-Jka is not available, typing could be done only by using CDP-treated cells that were DAT-negative.