Two universally conserved sequences from influenza type A neuraminidases were identified by large scale sequence analysis then chemically modified and conjugated to carrier proteins to generate mono-specific and monoclonal antibodies. The two antibodies, one targeting the N-terminus of the type A neuraminidase and the other sequence close to enzymatic active site, were capable of binding to all 9 subtypes of neuraminidase while demonstrating remarkable specificity against the viral neuraminidase sequences since no cross-reactivity against allantoic proteins was observed. Quantitative analyses of NA using slot blot suggest that the antibodies can be used for NA antigen quantitation in vaccines. These represent the first time the antibody-based immunoassay can be used for NA quantitative determination.