Accuracy of Urine and Serum Assays for the Diagnosis of Strongyloidiasis by Three Enzyme-Linked Immunosorbent Assay Protocols.

To evaluate the accuracy and reliability of urine assay for the diagnosis of strongyloidiasis, three different immunoassays were used to assess the diagnostic accuracy of anti-Strongyloides immunoglobulin G (IgG) in urine and compared with those in serum samples. Analyses by InBios enzyme-linked immunosorbent assay (ELISA) kit (recombinant NIE antigen), SciMedx ELISA kit (Strongyloides stercoralis antigen), and our in-house ELISA (Strongyloides ratti antigen) yielded comparable diagnostic performances between urine and serum assays. Levels of Strongyloides-specific IgG in urine significantly correlated with those in serum. Tests for diagnostic agreement between urine and serum IgG assays showed substantial to fair agreement (κ = 0.207-0.615). The observed quantitative and qualitative concordance between urine and serum assays in strongyloidiasis suggests that urine has similar diagnostic value to that for serum. Because of the ease and noninvasiveness of clinical sample collection, urine assay has a high potential for the initial diagnosis and mass screening of strongyloidiasis.