Diagnostic performance of urinary IgG antibody detection: A novel approach for population screening of strongyloidiasis

PLoS One. 2018 Jul 9;13(7):e0192598. doi: 10.1371/journal.pone.0192598. eCollection 2018.

Abstract

The diagnosis of strongyloidiasis by coprological methods has a low sensitivity, underestimating the prevalence of Strongyloides stercoralis in endemic areas. Serodiagnostic tests for strongyloidiasis have shown robust diagnostic properties. However, these methods require a blood draw, an invasive and labor-intensive sample collection method, especially in the resource-limited settings where S. stercoralis is endemic. Our study examines a urine-based assay for strongyloidiasis and compares its diagnostic accuracy with coprological and serological methods. Receiver operating characteristic (ROC) curve analyses determined the diagnostic sensitivity (D-Sn) and specificity (D-Sp) of the urine ELISA, as well as estimates its positive predictive value and diagnostic risk. The likelihood ratios of obtaining a positive test result (LR+) or a negative test result (LR-) were calculated for each diagnostic positivity threshold. The urine ELISA assay correlated significantly with the serological ELISA assay for strongyloidiasis, with a D-Sn of 92.7% and a D-Sp of 40.7%, when compared to coprological methods. Moreover, the urine ELISA IgG test had a detection rate of 69%, which far exceeds the coprological method (28%). The likelihood of a positive diagnosis of strongyloidiasis by the urine ELISA IgG test increased significantly with increasing units of IgG detected in urine. The urine ELISA IgG assay for strongyloidiasis assay has a diagnostic accuracy comparable to serological assay, both of which are more sensitive than coprological methods. Since the collection of urine is easy and non-invasive, the urine ELISA IgG assay for strongyloidiasis could be used to screen populations at risk for strongyloidiasis in S. stercoralis endemic areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Animals
  • Antibodies, Helminth / blood
  • Antibodies, Helminth / urine*
  • Antigens, Helminth / immunology*
  • Cross-Sectional Studies
  • Endemic Diseases*
  • Enzyme-Linked Immunosorbent Assay / methods
  • Feces / parasitology
  • Female
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin G / urine*
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • ROC Curve
  • Strongyloides stercoralis / immunology*
  • Strongyloides stercoralis / isolation & purification
  • Strongyloidiasis / blood
  • Strongyloidiasis / diagnosis*
  • Strongyloidiasis / epidemiology
  • Strongyloidiasis / urine
  • Thailand / epidemiology
  • Young Adult

Substances

  • Antibodies, Helminth
  • Antigens, Helminth
  • Immunoglobulin G

Grants and funding

This work was supported by the Office of the Higher Education Commission (CHE program) for the Ph.D. program (CE), the Higher Education Research Promotion and Office of the Higher Education Commission, through health cluster (SHeP-GMS) (PS) and Invitation Research fund (I 57116) (CE) from the Faculty of Medicine, Khon Kaen University, Thailand. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.