Evaluation of a rapid enzyme-linked immunosorbent assay for diagnosis of strongyloidiasis.

Diagnosis of strongyloidiasis using stool examination remains unsatisfactory due to the lack of sensitivity and fastidious techniques. In this work, we investigated the value of an anti-Strongyloides IgG enzyme immunoassay (EIA), using a panel of 207 sera retrospectively collected from patients with definitive diagnoses of strongyloidiasis (n=57), other helminthic infections (n=46), eosinophilia without parasitic infection diagnosis (n=54), and digestive disturbances following a tropical journey (n=30) and from 20 negative controls. By following a receiver operating characteristic (ROC) curve analysis, it was possible to optimize the test to reach a sensitivity of 91.2% and a specificity of 93.3%, with 92.8% of patients correctly classified. Considering the incidence of strongyloidiasis diagnosed in our own laboratory, the negative predictive value was calculated at 99.9%. In conclusion, this test is very rapid and easy to perform and may be valuable for diagnosis of strongyloidiasis both in cases where the infection is unrevealed by a parasitological stool examination and in patients at risk for severe clinical forms, such as patients receiving immunosuppressive therapy.