A Comparative Study on Measles Antibody in Healthy Persons by ELISA and HI test in Shanghai in 1999

In order to compare the hemagglutination inhibition (HI) test and the ELISA in detecting measles antibody, we randomly selected 505 healthy persons aged 0-20 years old from Pudong and Jinshan Districts of Shanghai. The results showed that these two tests were significantly correlated (r=0.58, P 0.0005), as indicated by the positive rates of measles antibody 99.01% and 93.66%, the geometric titers (GMT) 1∶26.0 and 1∶1 303.46 for HI test and ELISA respectively. The higher ELISA-IgG titers were parallel with the liters of HI. There were 5 blood specimens tested as negative (1∶2) by HI test while 32 were negative (1∶250) by ELISA, the coincident rate of the two tests was 94.4%. Detection of specific antibodies of measles by the two tests is different, HI test is for hemagglutinin antibody involving IgM and IgG and ELISA is for whole antibody of measles, including hemagglutinin-IgG, hemolysin-IgG, nuclear protein and so on. Antibody levels of measles detected with ELISA in persons aged ≥7 years old were lower since the IgG antibody of measles had decreased. Antibody levels detected with both HI test and ELISA in Jinshan District was higher, this might contribute to the boosted measles vaccination to the students in primary and middle schools in 1993 and 1997.