Capture vs. Detection
In a sandwich assay, the Capture Antibody (on the T-line) and Detection Antibody (on the Gold) must bind to different epitopes. Steric hindrance is a common failure mode.
Screening Protocol
We recommend a “Checkerboard” screening approach using Due Bio Universal Strips. Test Antibody A (Capture) against Antibody B (Detection), and then swap them. Often, one orientation yields 2-5x higher signal.