Diagnostic accuracy of five serologic tests for Strongyloides stercoralis infection

PLoS Negl Trop Dis. 2014 Jan 9;8(1):e2640. doi: 10.1371/journal.pntd.0002640. eCollection 2014.

Abstract

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.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Child
  • Child, Preschool
  • Diagnostic Tests, Routine / methods*
  • Female
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Parasitology / methods*
  • Retrospective Studies
  • Sensitivity and Specificity
  • Serologic Tests / methods
  • Strongyloides stercoralis / immunology*
  • Strongyloidiasis / diagnosis*
  • Young Adult

Grant support

This work has been partly supported by the EC within the 7th Framework Programme under the COHEMI project - grant agreement no. FP7-GA-261495. We thank Bordier Affinity Products SA for donating the Bordier ELISA kits. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.