Microneutralizing test is an alternative method to type and subtype influenza viruses. However, due to the needs of cell culture process, this method is labor-intensive and requires biological safety containments (particularly for high pathogenic strains). As such, it is not suitable for large scale investigations [19, 20] . Recently, subtyping of IAV antibodies using different categories of ELISA assays have also been reported [16, 17, 21] . However, present ELISA assays mainly rely on an HA antigen, which can lead to nonspecific detection to some extent due to the possible cross-reaction of different subtypes [22, 23] .