Case report: mixed-field agglutination in a patient with a weak D antigen presenting as a possible fetal-maternal hemorrhage

A gravida 1, para 0, 17-year-old black female was found on pre-natal testing to he group O, Du^u, the latter test showing many unagglutinated cells. Because of the mixed-field appearance, the patient was thought initially to have bad a fetal-maternal hemorrhage. Additional red cell typings were performed, but no other apparent mixed-field reactions were observed. The Kleihauer-Betke test and hemoglobin electrophoresis indicated that the mixed-field agglutination was not due to a fetal-maternal hemorrhage. Thus, the finding of a mixed-field D typing could he explained best by a weak D antigen. Immunohematology 1992;8:77-78.