Direct ELISA

Definition

Direct ELISA is a laboratory technique used to detect antigens in a sample using an enzyme-linked antibody that directly binds to the target antigen. It provides quick and specific results with fewer steps compared to other ELISA methods.

5 Must Know Facts For Your Next Test

1. Direct ELISA involves an antibody directly linked to an enzyme, eliminating the need for a secondary antibody.
2. It is commonly used to detect the presence of specific proteins or pathogens in various samples.
3. The assay's sensitivity can be affected by the direct binding of the enzyme-linked antibody, potentially leading to lower sensitivity compared to other ELISA formats.
4. Color change occurs when the enzyme reacts with its substrate, indicating the presence and quantity of the antigen.
5. This method is faster and simpler than indirect or sandwich ELISAs but may have limited amplification due to lack of secondary antibodies.

Review Questions

• What is the main advantage of using Direct ELISA over other types of ELISAs?
• How does Direct ELISA achieve specificity in detecting target antigens?
• What potential limitation affects the sensitivity of Direct ELISA?

Related terms

Indirect ELISA:

An assay where a primary antibody binds to the antigen and a labeled secondary antibody binds to the primary antibody.

Sandwich ELISA:

A method where two antibodies are used; one captures the antigen and another labeled antibody detects it.

Antigen:

A substance that induces an immune response, often targeted in immunoassays like ELISAs.