Approval for introduction of a new instrument model, the immulite 2000 xpi analyzer, as a new family member of the currently approved immulite 2000 analyzer, to be used with the currently approved immulite 2000 anti-hbs assay. the device, as modified, will be marketed under the trade immulite 2000 xpi anti-hbs assay and is indicated for in vitro diagnostic use for the detection of anti-hbs and is indicative of laboratory diagnosis of seroconversion from hepatitis b virus (hbv) infection.