[Comparison of positivity rates for antibodies against measles, rubella, chickenpox and mumps by assays].

Our previous study found mistakes by some doctors in the choice of an assay for determining antibodies in Japan. To compare the positivity rates for antibodies by assays, we measured the antibodies of measles, rubella, chickenpox and mumps from the same sera using such methods as the EIA, HI and CF assays. The subjects were 175 nursing students. The positivity rates for measles, chickenpox and mumps by the EIA assay were 96.6%, 93.7%, and 83.3%, respectively. Those for rubella by the HI and CF assays were 92.0% and 10.1%. The sensitivity rates for measles, chickenpox and mumps by the HI and CF assays, based on the results of the EIA assay, were 75.1%, 102.4% and 69.2% in the HI assay, and 20.6%, 38.7% and 8.0% in the CF assay, respectively. Our previous study showed that the sensitivity of the HI assay for rubella antibody is same as that of the EIA assay in Japan. Currently an EIA assay should be chosen for these antibodies and the HI assay or IAHA assay should be possible selections for rubella and chickenpox. However, international comparison of the cutoff titers for these antibodies should be considered.