A delayed hemolytic transfusion reaction due to anti-Cob.

A delayed hemolytic transfusion reaction precipitated by anti-Cob is described in a multiple transfused primigravida woman with sickle-cell disease. Sixteen days after the prophylactic transfusion of the first of 4 units of red cells, she experienced a fall in hemoglobin concentration accompanied by a newly positive antibody screen and direct antiglobulin test. Anti-Cob was identified both in the patient's serum and in an eluate prepared from her red cells.