HBsAg Rapid Test (Cassette) RapiCardInstaTest (Serum, Plasma, WB Test ), Export ... It is used as an aid in the diagnosis of hepatitis B infection and screening of ... for qualitative detection of the surface antigen of hepatitis B virus (HBsAg) in ... to HBsAg (sAb-Au) are dryimmobilized onto a nitrocellulose membrane strip.