Journal of the Oman Medical Association
Signal- and Bead-Dependent Inter-Operator Variability in Single-Center Luminex-Based HLA Antibody Testing
By Cristiana Teixeira, Isaias Pedro, Isabel Silva and 1 others.
Abstract
Background
Luminex-based single antigen bead assays are widely used for HLA antibody assessment in transplantation, but their semi-quantitative fluorescence outputs may be affected by technical, signal-dependent, and bead-specific factors. This single-center study evaluated inter-operator variability under routine laboratory conditions.
Methods
Twenty serum samples were tested for each assay format: Class I SAB, Class II SAB, and screening. For each assay type, the same serum set was independently tested by four trained operators using the same Luminex FlexMap 3D instrument and xPONENT software version 4.3. Sera were EDTA treated, and exported trimmed mean fluorescence intensity values were analyzed at the sample–bead level. Variability was assessed using log-transformed inter-operator spread, threshold-based discordance, variance decomposition, direct item-level operator deviations, and bead-level variability profiling.