Commercial ELISA kits that detect antibodies against the nucleocapsid protein are available. Kits with
an indirect and competitive/blocking format have been developed and validated, and are now being
used to detect influenza A virus-specific antibodies. SSeveral avian influenza competitive ELISA (AIV CELISA)
or blocking ELISA (AIV B-ELISA) have been developed and validated as a more sensitive
alternative to the AGID test for the detection of influenza A group reactive antibodies in sera from
chickens and other bird species