COMPARISON OF ENZYME IMMUNOASSAYS FOR ANTIBODIES TO HAEMOPHILUS-DUCREYI IN A COMMUNITY OUTBREAK OF CHANCROID IN THE UNITED-STATES

The performance of two EIAs (adsorption EIA and lipooligosaccharide [L OS] EIA) that detect antibodies to Haemophilus ducreyi was evaluated w ith serum specimens obtained from 163 patients (96 with genital ulcer disease [GUD]). Paired serum specimens (initial and follow-up) were ob tained from 52 of the GUD patients. By use of initial serum specimens from 82 GUD patients whose etiologic agents for their ulcers had been identified, the adsorption EIA had a sensitivity and specificity for c hancroid of 53% and 71%, while the LOS EIA had a sensitivity and speci ficity of 48% and 89%, respectively. Sensitivity and specificity of th e adsorption ELA increased to 78% and 84%, respectively, when the resu lts of follow-up serum specimens were used to calculate optimal perfor mance. The proportion of patients testing positive for H. ducreyi who had anti-H. ducreyi IgG antibodies, as determined by adsorption EIA, i ncreased with the duration of infection, thus limiting the role of EIA s in the diagnosis of chancroid.