Technical and Diagnostic Performance of Five Commercial

The technical and diagnostic performances of five commercially available enzyme-linked immunosorbent assays for the measurement of anti-diphtheria toxoid IgG antibodies were evaluated. There was good agree-ment between the relative sensitivities of the five assays, but the relative specificity of one of the assays differed from that of the other four assays. Three of the five assays possessed recoveries of the international reference material NIBSC 00/496 within the range of 90 % to 110 % at antibody levels>0.1 IU/ml. The data suggest that there are manufacture-dependent differences in relative sensitivity, specificity, and accuracy for the determi-nation of anti-diphtheria toxoid IgG antibodies that could result in different diagnostic interpretations. Diphtheria is caused by toxigenic strains of Corynebacterium diphtheriae and is almost entirely preventable through a regular immunization schedule (9). Since routine immunization against diphtheria has become standard practice in industrial-ized nations, clinical cases are rare; however, it is still a prob-lem in many developing countries, such as the new nations formed from the breakup of the former Soviet Union (29), as well as in people without adequate immunity