Precision of Serologic Testing from Dried Blood Spots Using a Multiplex Bead Assay

Area of Science:

• Immunology
• Infectious Diseases
• Public Health

Background:

• Multiplex bead assays (MBAs) are increasingly used in serologic testing for public health surveys.
• Limited studies have evaluated the test performance of MBAs, particularly with dried blood spots (DBS).

Purpose of the Study:

• To assess the test performance characteristics of multiplex bead assays (MBAs) for serologic testing using dried blood spots (DBS).
• To evaluate antibody responses against 13 antigens from nine infectious organisms.

Main Methods:

• Dried blood spots (DBS) were collected from 393 children in Ethiopia.
• Samples were processed using a Luminex-based MBA to detect antibodies against 13 antigens.
• Assays were run with varying bead counts (50 and 100 beads per well) and compared for reproducibility.

Main Results:

• High agreement was observed between multiple runs of the MBA on DBS samples.
• Intraclass correlation coefficients exceeded 0.85 for Salmonella antibodies and 0.95 for others.
• Cohen's kappa statistics for seropositivity indicators were consistently above 0.87, indicating strong reliability.

Conclusions:

• Serologic testing using multiplex bead assays on the Luminex platform exhibits robust performance characteristics.
• The findings support the utility of MBAs with DBS for reliable antibody detection in public health surveillance.