Sandwich Immunoassay
An analytical method using two antibodies to capture and detect an analyte, creating a 'sandwich' configuration.
Full Definition
A sandwich immunoassay is a highly specific analytical technique commonly used for measuring protein hormones and larger molecules. The method employs two different antibodies: a capture antibody immobilized on a solid phase that binds the analyte, and a detection antibody (often labeled with an enzyme, fluorophore, or chemiluminescent compound) that binds to a different epitope on the same analyte molecule. This creates a sandwich-like structure with the analyte between two antibodies. The signal is directly proportional to the analyte concentration, making it ideal for measuring hormones like TSH, LH, FSH, and growth hormone. This format generally offers superior specificity compared to competitive assays.
In Context
- "TSH measurement employs a sandwich immunoassay configuration for optimal sensitivity and specificity." — Analytical method description
- "The sandwich immunoassay format requires the analyte to have at least two distinct epitopes." — Assay development protocol