DETECTION OF HEPATITIS-B SURFACE-ANTIGEN IN WHOLE-BLOOD BY COUPLED PARTICLE LIGHT-SCATTERING (COPALIS(TM))

Coupled particle light scattering (Copalis(TM)) is a homogeneous immun oassay technology that permits simultaneous determination of multiple analytes in serum, plasma, or whole blood. Copalis differentiates mono meric latex microparticles from latex aggregates and cells on the basi s of their unique light scatter properties. Copalis readily discrimina tes small (similar to 0.1 mu m) differences in latex microparticle siz e, Therefore, multiple simultaneous assays are configured by the use o f mixtures of different-size latex microparticles. The Copalis researc h immunoassay for hepatitis B surface antigen (HBsAg) is configured in a sandwich format where the extent of light scatter histogram broaden ing due to HBsAg-mediated binding of colloidal gold to latex provides the basis for antigen quantification, Simultaneous Copalis forward- an d wide-angle light scatter measurements allow discrimination of latex microparticles from the cell components of whole blood. Consequently, direct detection of HBsAg in unprocessed whole-blood samples by Copali s is feasible.