Step 1: Define ELISA.
ELISA is a test used to detect the presence of antibodies or antigens in a sample using an enzyme-linked antigen or antibody.
Step 2: Break down the acronym.
- Enzyme: A protein that catalyzes reactions.
- Linked: The enzyme is linked to the antigen or antibody.
- Immunosorbent: Refers to the binding of the antibody or antigen.
- Assay: A test or analysis.
Step 3: Conclude.
ELISA stands for Enzyme-linked immunosorbent assay.
Final Answer:
\[
\boxed{\text{Enzyme-linked immunosorbent assay}}
\]