Cloned enzyme donor immunoassay

Cloned Enzyme Donor Immunoassay (CEDIA)

Cloned Enzyme Donor Immunoassay (CEDIA) is a biochemical assay technique used in clinical chemistry to measure the concentration of specific substances, typically small molecules, in a sample. This method is widely used in toxicology, therapeutic drug monitoring, and clinical diagnostics.

Principle of CEDIA

CEDIA is based on the principle of enzyme complementation. The assay uses two fragments of an enzyme that are inactive when separate but become active when combined. These fragments are known as the enzyme donor (ED) and the enzyme acceptor (EA). In CEDIA, the ED is genetically engineered and cloned, allowing for consistent and reproducible assays.

The target analyte in the sample competes with a labeled analyte for binding to a specific antibody. The labeled analyte is conjugated to the ED. When the labeled analyte is not bound to the antibody, it can combine with the EA to form an active enzyme, which catalyzes a reaction that produces a measurable signal, usually a color change. The intensity of the signal is inversely proportional to the concentration of the target analyte in the sample.

Applications

CEDIA is used in various applications, including:

• Therapeutic Drug Monitoring: Measuring drug levels in patients to ensure they are within the therapeutic range.
• Toxicology: Detecting and quantifying drugs of abuse and other toxic substances.
• Clinical Diagnostics: Measuring hormones, metabolites, and other biomarkers in blood or urine samples.

Advantages

CEDIA offers several advantages over other immunoassay techniques:

• High Specificity and Sensitivity: Due to the use of specific antibodies and enzyme complementation.
• Wide Dynamic Range: Capable of measuring a broad range of analyte concentrations.
• Automation Compatibility: Easily integrated into automated systems for high-throughput testing.

Limitations

Despite its advantages, CEDIA has some limitations:

• Interference: Potential for interference from substances in the sample that affect enzyme activity.
• Cost: May be more expensive than other simpler assay methods.

Also see

• Enzyme-linked immunosorbent assay (ELISA)
• Radioimmunoassay (RIA)
• Fluorescence polarization immunoassay (FPIA)
• Mass spectrometry