The disclosure concerns a polypeptide suitable for detecting antibodies against Zika virus in an isolated biological sample having a Zika virus NS1 wing domain specific amino acid sequence and variants thereof, wherein no further Zika virus specific amino acid sequences are present in the polypeptide. This polypeptide does not immunologically cross-react with antibodies raised against structurally related antigens from tick-borne encephalitis virus, Dengue virus 1-4, West Nile virus, yellow fever virus or Japanese encephalitis virus, but immunologically reacts with antibodies raised against full length Zika virus NS1 antigen. Also disclosed is a method of producing a soluble and immunoreactive Zika virus NS1 polypeptide as well as methods and kits for detecting antibodies specific for Zika virus in an isolated sample.