Validierung eines Enzymimmunoassays zur Bestimmung des Diphtherieimmunstatus vor und nach Impfung

Purpose: Assessment of an Easy-to-Perform Immunoenzymatic Assay for Detecting Diphtheria Immunity in the Population. Can an immunoassay replace or support the toxin neutralisation test? Sera and methods: Sera of 75 adults were collected before and after vaccination and tested in the vero cell neutralisation test and the immunoassay. Results: The sensitivity of the EIA was 73 and 94%, specificity was 74 and 67% before and after vaccination, respectively. Positive or negative predictive value was 70 and 96% or 78 and 49% before and after vaccination, respectively. The correlation coefficient changed from 0.43 to 0.77 after vaccination. A comparison of the quantitative results of the test showed differences up to 19 times in individual cases. Conclusions: Only cases with relatively high antibody titres (e.g. after booster vaccination) show EIA high sensitivity. Linear correlation is also high in such cases. If you expect low antitoxin levels as is the case before booster vaccination, EIA will then often be false positive or negative. Such studies should be limited to the neutralisation method.