I am working on developing lateral flow immunoassays for drugs of abuse and needed some advice on detecting multiple drug compounds in one immunoassay.
As an example, an existing LFIA on the market tests for amphetamines, and detects the following compounds as positive at varying levels:
- 3,4-Methylenedioxyamphetamine (MDA)
These compounds are all tested in one test strip — not multiplexed; the presence of any one of those compounds above the cut-off level will cause the single test strip to show a positive.
I don't quite understand how antibodies work and have a few theories:
- Polyclonal antibodies have been used on the test line, which means all these compounds are detected
- A mixture of monoclonal antibodies have been used, to detect all these compounds
- These compounds are all chemically similar enough to be reliably detected with a single monoclonal antibody
Which of the above would be correct? Or am I misunderstanding this entirely and the answer is something different?