Figure 1.

Schematic representation of the sandwich ELISA technique used. CGRP molecules in buffered plasma are bound by the capture antibodies that are fixed to the well. Other CGRP epitopes bind tracer antibodies conjugated with acetyl choline esterase (AchE), which converts Ellman’s reagent (DTNB) to TNB that gets ionized and appears yellow. Not CGRP- bound tracer antibodies are washed away. The amount of TNB²⁻ is proportional to the amount of AchE-conjugated antibodies and hence CGRP molecules.