Enzyme-linked
immunosorbent assays for
IgM antirubella were carried out on 1,546 sera, using an
IgM capture method with a F (ab')2 conjugate (ACCA). Under the conditions described, sera containing
IgM antirubella bound up to 15 times as much
enzyme activity as negative specimens. Paired serum specimens from 27 patients, serial serum specimens from 6 patients, and single serum specimens from 15 patients who had had recent
rubella were examined by the haemagglutination inhibition test (HAI) in the presence and absence of
2-mercaptoethanol following
sucrose density gradient centrifugation (SDGC). ACCA confirmed all the results found with HAI following SDGC. Specimens were examined from ten patients with congenital
rubella; ACCA confirmed the results found with both immunofluorescence following SDGC and radioimmunoassay. Pre- and post-vaccination specimens from 123 patients who had been vaccinated against
rubella were examined. An
IgM response could only be demonstrated in the 57 cases when
IgG was absent in the first specimen. The specificity of the assay was confirmed by testing 31 serum specimens from
rubella immune patients that also contained
rheumatoid factor, 163 serum specimens from patients with acute
infections other than
rubella, and 12 serum specimens from infants with miscellaneous neonatal abnormalities other than congenital
rubella. The ACCA proved a simple, sensitive, and specific test for
IgM antirubella and the results compared favourably with those obtained by the SDGC technique.