The key difference between CLIA and ECLIA is that CLIA uses a chemical method to generate chemiluminescence while ECLIA uses an electrochemical method to generate chemiluminescence signals in the immunoassay technique.
Immunoassays are widely used in the identification and quantification of proteins associated with diseases or infections. Therefore, they primarily rely on the concept of antibody-antigen binding. There are many types of immunoassays, and chemiluminescent immunoassays one such emerging developmental technique. Both CLIA and ECLIA use chemiluminescent indicators.
What is CLIA?
Chemiluminescent Immunoassay (CLIA) is a type of immunoassay that uses a luminescent molecule for detection. The luminescence emitted by the molecule is detected on the spectrophotometer, generally at a wavelength between 300 – 800 nm. The chemiluminescence causes excitation of the atoms, and the technique identifies exergonic chemical reactions to be the most suitable energy source to produce excitation.
The CLIA technique takes place in two main methods as direct CLIA technique and indirect CLIA technique. The direct CLIA technique uses direct luminophore markers that are bound to the target, while the indirect CLIA method uses enzymatic markers. The direct luminophore markers include acidum and ruthenium esters while the indirect markers include alkaline phosphatase with adamantyl 1, 2-dioxetane aryl phosphate (AMPPD) substrate and horseradish peroxidase with luminol or its derivatives as substrate.
The key advantages of CLIA are the wide dynamic range of functionality, high intensity in signal delivery, absence of background interference, high specificity, rapidness, stability and compatibility to different assay protocols. In contrast, their high cost, and limitations with regards to antigen detection and test panels are the disadvantages of CLIA.
What is ECLIA?
Electrochemiluminescence Immunoassay (ELCIA) is a novel technique of immunoassay development that uses the concept of electrochemiluminescence. In the concept of electroluminescence, the intermediates generate electrochemically. These electronically generated intermediates then reach an excited state and result in the emission of light. The wavelength in which the light is emitted corresponds to the energy gap. Chemiluminescence is, thus, produced owing to one or more reactants being produced electrochemically on the electrode.
ECLIA is a useful analytical application with high sensitivity and specificity. It is mainly used in identifying proteins related to different pathological and medical conditions. Its key advantages include wider dynamic range, versatility, spatial and temporal control by applying electrode potentials, high sensitivity up to picomolar ranges. However, the fact that it requires expert handling and the high cost associated are its disadvantages.
What are the Similarities Between CLIA and ECLIA?
- Both techniques rely on the concept of antigen-antibody binding.
- Moreover, both are mainly used for disease diagnostics based on protein quantification.
- Both are sensitive and specific kit methods.
- They use the concept of chemiluminescence for detection.
- They can be automated.
- Both require a spectrophotometer for detection.
- Both have a wide dynamic range.
- They are costly techniques.
What is the Difference Between CLIA and ECLIA?
CLIA is a technique of immunoassay that uses the theory of chemiluminescence, while ECLIA is a technique of immunoassay that uses the theory of electrochemistry coupled with chemiluminescence. So, this is the key difference between CLIA and ECLIA. Therefore, CLIA uses chemical reactions that lead to the development of chemiluminescent signals, while ECLIA uses electrochemical reactions that lead to the development of chemiluminescent signals.
The below infographic of the difference between CLIA and ECLIA shows more comparisons between both techniques.
Summary – CLIA vs ECLIA
CLIA and ECLIA are both techniques that play an important role in disease diagnostics. They are advanced methods of immunodiagnostics based on the concept of antibody-antigen binding. The key difference between CLIA and ECLIA is the method of generating chemiluminescence. While CLIA uses chemical reactions to generate chemiluminescence following antibody-antigen binding, ECLIA uses electrochemical reactions to generate chemiluminescence. However, both techniques are rapid and specific.
1. Cinquanta, Luigi, et al. “Chemiluminescent Immunoassay Technology: What Does It Change in Autoantibody Detection?” Auto- Immunity Highlights, Springer International Publishing, Dec. 2017, Available here.
2. “ECLIA Based Kits Development.” ECLIA Based Kits Development – Creative Biolabs, Available here.