Evaluation of a passive hemagglutination test kit for the detection of rubella antibodies.

RUBACELL (Abbott Laboratories), a commercial test kit for the detection of rubella antibodies that utilizes the principle of passive hemagglutination (PHA), was compared with a standard hemagglutination-inhibition (HI) assay procedure. The PHA test gives a qualitative yes/no result suitable for pregravidic determination of immune status. The procedure is technically simple and requires less than half the time needed for the HI assay. Four of 61 sera that were negative with HI assay tested as indeterminate or as falsely positive using the RUBACELL procedure.