RonL.

Hi, Maybe the positive Jka typing was really the baby's phenotype, since she was an ob patient. Solid phase is pretty sensitive. Possibly mom's ab's are now sitting on the baby's cells, accounting for her negative post screen. You can retest the neg screen in solid phase, incubating longer, up to an hour, to see if anything shows up. It would be interesting to see if the baby has a positive direct coombs upon birth.