Academic Journal

Serum as an alternative to plasma for determining the ApoE4 phenotype using Pan-ApoE and ApoE4 chemiluminescent enzyme immunoassays.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος: Serum as an alternative to plasma for determining the ApoE4 phenotype using Pan-ApoE and ApoE4 chemiluminescent enzyme immunoassays.
Συγγραφείς: Kortmann, Eric, Steinacker, Petra, Guthknecht, Arthur, Weise, Christopher M., Otto, Markus
Πηγή: Clinical Chemistry & Laboratory Medicine; Aug2026, Vol. 64 Issue 9, p1997-2006, 10p
Θεματικοί όροι: Apolipoprotein E4, Blood plasma, Chemiluminescence immunoassay, Genotypes, Biomarkers, Blood sampling, Alzheimer's disease
Περίληψη: Since apolipoprotein E4 (ApoE4) is associated with therapy-related adverse effects of anti-amyloid-β monoclonal antibodies in Alzheimer's disease, such as amyloid-related imaging abnormalities, methods for determining the ApoE4 status are needed. The Lumipulse® ApoE4 and Pan-ApoE assays provide a practical approach, but they have so far been validated only in plasma. Plasma and serum obtained from a single blood draw from 157 patients were analyzed using ApoE4 and Pan-ApoE chemiluminescent enzyme immunoassays. The APOE genotype was determined by allele-specific quantitative polymerase chain reaction. Additional experiments assessed assay repeatability, intermediate precision, and sample stability under various storage conditions. ApoE4, Pan-ApoE, and the resulting ApoE4/Pan-ApoE ratio showed minimal bias, strong positive correlation and linearity between plasma and serum. Using matrix-specific thresholds, plasma- and serum-derived ApoE4/Pan-ApoE ratios accurately classified the ApoE4 phenotypes in concordance with APOE ε4 genotypes. The assay demonstrated repeatability of <15 % and <5 % (day 1 and 2), with intermediate precision <10 % for both Pan-ApoE and ApoE4. Plasma and serum showed both comparable stability after multiple freeze-thaw-cycles and up to 120 h at 4 °C, while serum showed deterioration after 120 h storage at 20 °C. Using matrix-specific thresholds, the ApoE4/Pan-ApoE ratio in plasma and serum accurately classified the ApoE4 phenotype in concordance with APOE ε4 genotypes. Serum and plasma showed comparable stability and precision. Thus, serum is a reliable alternative to plasma for measuring Pan-ApoE and ApoE4 with the Lumipulse assays. The use of serum expands sample availability, particularly in retrospective studies or when collected alongside cerebrospinal fluid. [ABSTRACT FROM AUTHOR]
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