Accuracy of an Automated Plasma Apolipoprotein E4 Proteotyping Immunoassay for Determination of <i>APOE</i> Genotype

The evaluated plasma apoE4 phenotyping assay demonstrated perfect accuracy in detecting the presence or absence of an E4 allele. However, it did not reliably distinguish E4 heterozygotes from homozygotes, with several heterozygotes misclassified as E4/E4. In the context of AAT treatment eligibility and ARIA risk assessment, proteotyping is an accurate method for both ruling in and out the presence of an E4 allele but E4/E4 results specifically should be confirmed via genotyping.