The performances of 2 commercial enzyme-linked immunosorbent assay (ELISA) kits (PLATELIA Dengue NS1 AG and Dengue Early ELISA) and a rapid immunochromatography test (Dengue NS1 AG Strip) for detection of dengue NS1 protein were compared using a panel of 87 sera from viremic dengue patients, as well as 36 sera from patients with other acute febrile illnesses. PLATELIA was more sensitive and slightly less specific than Dengue Early ELISA (sensitivity, 71.3% versus 60.9%; specificity, 86.1% versus 94.3%, respectively). The strip test showed an overall sensitivity of 67.8% with a specificity of 94.4%. A lower sensitivity was observed with Dengue Early ELISA for dengue virus (DENV) type 4 (30%) and by the 3 tests for DENV type 2 (56.5%). The use of these kits allows for rapid and specific early diagnosis of dengue infection; however, their sensitivity for each serotype must be further evaluated to guarantee an accurate diagnosis, particularly in those regions where the 4 dengue serotypes are cocirculating.