Diagnostic Accuracy of Five Serologic Tests for Strongyloides stercoralis Infection

Background:the diagnosis of strongyloides stercoralis (s. stercoralis) infection is hampered by the suboptimal sensitivity of fecal-based tests. serological methods are believed to be more sensitive,although assessing their accuracy is difficult because of the lack of sensitivity of a fecal-based reference (gold) standard.methods:the sensitivity and specificity of 5 serologic tests for s. stercoralis (in-house ifat,nie-elisa and nie-lips and the commercially available bordier-elisa and ivd-elisa) were assessed on 399 cryopreserved serum samples. accuracy was measured using fecal results as the primary reference standard,but also using a composite reference standard (based on a combination of tests).results:according to the latter standard,the most sensitive test was ifat,with 94.6% sensitivity (91.2-96.9),followed by ivd-elisa (92.3%,87.7-96.9). the most specific test was nie-lips,with specificity 99.6% (98.9-100),followed by ivd-elisa (97.4%,95.5-99.3). nie-lips did not cross-react with any of the specimens from subjects with other parasitic infections. nie-lips and the two commercial elisas approach 100% specificity at a cut off level that maintains ≥70% sensitivity.conclusions:nie-lips is the most accurate serologic test for the diagnosis of s. stercoralis infection. ifat and each of the elisa tests are sufficiently accurate,above a given cut off,for diagnosis,prevalence studies and inclusion in clinical trials.