A biomarker assay is a test designed to measure a biological molecule associated with a disease state, biological process, treatment response, or research question. Reliable biomarker assays require well-characterized reagents, appropriate sample handling, and fit-for-purpose validation.

A sample matrix is the biological material in which a target analyte is measured, such as serum, plasma, CSF, tissue lysate, or cell culture supernatant. Matrix selection matters because each sample type can affect antibody binding, background signal, and assay performance differently.

Dynamic range is the concentration span over which an assay can accurately measure an analyte. A useful dynamic range should cover the expected concentration of the biomarker in the relevant sample type.

Cross-reactivity occurs when an antibody binds to a molecule other than the intended target, often because of shared or similar epitopes. Reducing cross-reactivity is important for assay specificity and confidence in the measured signal.

Specificity describes an antibody or assay’s ability to detect the intended target without significant interference from related or unrelated molecules. Specificity is especially important when measuring protein families, isoforms, post-translational modifications, or low-abundance biomarkers.

Reproducibility refers to the ability to obtain consistent results across experiments, operators, reagent lots, instruments, or sites. In antibody-based assays, reproducibility depends on reagent consistency, assay design, validation, and sample handling.

Use these glossary terms alongside Aviva’s technical resources, case studies, and service information to better understand how antibody characterization and assay development decisions shape biomarker measurement.

• Recombinant Antibody Discovery and Development White Paper 
• Aviva’s Workflow Built for Biomarker Measurement: A Case Study
• 3 part series: How to Design, Fine-Tune, and Validate Your ELISA Assays