Elimination of false-positive cytomegalovirus immunoglobulin M-fluorescent-antibody reactions with immunoglobulin M serum fractions

Abstract

The cytomegalovirus fluorescent-antibody test for immunoglobline M (IgM) antibody was found positive in seven of nine infants with congenital rubella infection, in addition to eight of eight infants with confirmed cytomegalovirus infection. When the test was repeated on IgM fractions of the same sera freed from IgG by ultracentrifugation, only negative reactions were observed in those from the rubella-infected infants, whereas IgM fractions from the cytomegalovirus-infected infants remained positive.