ELISA Tests

The ELISA (Enzyme-Linked Immunosorbent Assay) test is a widely used analytical method designed to detect and quantify specific molecules, such as proteins, peptides, hormones, and antibodies, in a liquid sample. It leverages antigen-antibody interactions and an enzyme-linked detection system to produce a quantifiable signal.

ELISA Test Procedure

• Coating:
  • Objective: Immobilize the target molecule (antigen or antibody) onto a solid surface, typically a microtiter plate.
  • Process: The wells of a microtiter plate are coated with capture antibodies (if detecting an antigen) or antigens (if detecting antibodies). The plate is incubated to allow binding.
• Blocking:
  • Objective: Prevent non-specific binding of proteins to the plate surface.
  • Process: A blocking solution, often containing proteins like bovine serum albumin (BSA) or non-fat dry milk, is added to block unoccupied sites on the plate.
• Sample Addition:
  • Objective: Introduce the sample to the wells to allow specific binding to the immobilized capture molecules.
  • Process: The sample containing the target analyte is added to the wells. If the target molecule is present, it will bind to the capture antibodies or antigens.
• Detection:
  • Objective: Identify and quantify the bound target molecule.
  • Process: A secondary antibody or antigen, which is conjugated to an enzyme (such as horseradish peroxidase or alkaline phosphatase), is added. This binds to the target molecule, forming a complex.

Applications

ELISA is employed in various fields such as clinical diagnostics (e.g., hormone levels, infection detection), research (e.g., biomarker studies), and quality control (e.g., detecting contaminants in food products). Its sensitivity, specificity, and quantitative capabilities make it a fundamental tool in both research and clinical laboratories.