Strongyloides stercoralis is an intestinal nematode endemic that affects an estimated 30 to 100 million people worldwide. Many of these individuals may be asymptomatic for decades. The present invention discloses a NIE recombinant antigen that can be used in improved assays and diagnostics for S. stercoralis infection. The NIE antigen is the only one that is non-cross-reactive with sera from humans with other related filaria infections. The NIE antigen can be utilized as a skin test antigen for immediate hypersensitivity as well as for use in ELISA or other assays.