Sera from 2,148 patients were tested with a third-generation microparticle
enzyme immnnoassay (MEIA), a confirmatory assay, and a reverse transcriptio
n-PCR. Overall, 85.6% of reactivities were confirmed, 13.2% were shown to b
e unspecifically reactive, and 1.2% were indeterminate. The rate of confirm
ed MEIA reactivities clearly depended on the strength of the reactivity.