Tetanus antibody assay combining in-house ELISA and particle agglutination test and its serosurvey application in a province in Turkey.

In order to determine a practically useful quantitative assay method for tetanus antibody in a large-scale seroepidemiological study, a method combining an in-house ELISA with a particle agglutination test (KPA) was evaluated in comparison with the in vivo mouse neutralization test. Serum samples with mouse neutralization antibody titers 0.01 IU/ml (the minimum protective level) or below showed considerable overestimation of antitoxin titers up to 1.0 IU/ml when studied by in-house ELISA alone. On the other hand, the KPA values were highly correlated with the mouse test, even in cases of titers equal to 0.01 IU/ml or below. The combination of these two procedures, in which in-house ELISA values of 1.0 IU/ml or below were replaced by KPA values, provided a high correlation in antibody titers with the mouse test (r = 0.968). We applied this combined method to a tetanus seroepidemiological survey in a province in Turkey. The survey included 347 subjects from the healthy population, and the quantitative analyses showed high antibody levels in children and young adults and significantly low levels among adults aged 40 or over. A characteristic distribution of antibody titers in each age group was also demonstrated.