Chemiluminescence immunoassay methods

Chemiluminescence immunoassay methods have many applications (Weeks, 1992). Highly sensitive chemiluminescent immunoassays were developed by Tsuji et al. (1989) for determination of enzymes (oxidases, peroxidase, glucose oxidase, P-D-galactosidase) as well as various hormones and drugs in biological fluids (Tsuji et al., 1989). 

Singh, A. K., Y. Jiang, J. T. White, and D. Spassova. 1997. Validation of nonradioactive chemiluminescent immunoassay methods for the analysis of thyroxine and cortisol in blood samples obtained from dogs, cats and horses. Journal of Veterinary Diagnostic Investigation 9 261-268. 

Clinically important drugs, such as methotrexate 4-amino-lO-methyl folic acid MTX - which has considerable significance as an antileukaemic agent can be assayed using chemiluminescence immunoassay methods, coupling the drug with firefly luciferase. 

The methotrexate assay [130] is described in some detail, as it can serve as an example of the chemiluminescence immunoassay method in general [131],... 

In the most common method for chemiluminescent immunoassay (GLIA), after the immunological reaction and any necessary separation steps, the labeled compounds or complexes react with an oxidizer, eg, hydrogen peroxide, and an enzyme, eg, peroxidase, or a chelating agent such as hemin or metal... 

Immunoaffinity chromatography (IAC), 6 400—402 12 137, 145 Immunoanalyzers, automated, 14 150 Immunoassay(s), 14 135-159. See also Immunoassay- DNA probe hybrid assays Immunoassay methods Immuno(bio)sensors antibody-antigen reaction, 14 136-138 basic technology in, 14 138-140 chemiluminescent, 14 150-151 classification of, 14 140-153 design of, 14 139-140 enzyme, 14 143-148 fluorescence, 14 148-150 highly specific, 14 153 historical perspective on, 14 136 microarrays and, 14 156—157 microfluidics in, 26 968—969 monoclonal versus polyclonal antibodies in, 14 152-153... 

Methods based on chemiluminescent and bioluminescent labels are another area of nonisotopic immunoassays that continue to undergo active research. Most common approaches in this category are the competitive binding chemiluminescence immunoassays and the immunochemiluminometric assays. Chemiluminescence and heterogenous chemiluminescence immunoassays have been the subject of excellent reviews (91, 92). Detection in chemiluminescence immunoassays is based on either the direct monitoring of conjugated labels, such as luminol or acridinium ester, or the enzyme-mediated formation of luminescent products. Preparation of various derivatives of acridinium esters has been reported (93, 94), whereas a variety of enzyme labels including firefly or bacterial luciferase (70), horseradish peroxidase (86, 98), and alkaline phosphatase are commercially available. 

Immunoassay- and chemiluminescence-based methods have also been used [337] to determine methyl-2-bendimadazole carbamate [338] and aldicarb and paraoxon in soil. 

Fan and Zhang determined acetylcholine and choline in rat brain tissue by a fluorescence immunoassay method, making use of immobilized enzymes and chemiluminescence detection [50]. Tissue was homogenized with a 10 fold volume of 0.6 M HC104, the homogenates were kept on ice for 30 min, and then centrifuged at 2000 G for 20 min. The pellets were... 

Most immunoassays currently employed in the biomedical field are either radioimmunoassays, enzyme immunoassays, or luminescence immunoassays (including fluorescence immunoassays [FIA] and chemiluminescence immunoassays). Although radioimmunoassay is currently the most sensitive of these (10 -10 M concentrations are often detectable), due to the problems inherent to dealing with radioactive materials, such as licensing, radiation hazard, short shelf-life of expensive radioisotopes, the expense of the counting equipment, and the tedium associated with heterogeneous immunoassay, it has fallen, in popularity, behind the non-isotopic methods of analysis. 

Chemiluminescence immunoassay,a technique that has rapidly gained popularity because its sensitivity is comparable to that of radioimmunoassay, is in a sense a variation of FIA. In the 1930s, the first work on chemiluminophores was published, but it was not until the 1980s that chemiluminescence was first tried in immunoassays. Due to the increased use of automated immunoassay analyzers, chemiluminescence has become one of the most common immunoassay detection methods used in the clinical laboratory setting. Chemiluminescence (also called bioluminescence when it occurs in fireflies and some dinoflagellates, coelente-rates, and fungi) is fluorescence. However, what is... 

Although AFP was traditionally measured by RIA, newer methods use lEMA or chemiluminescent immunoassay (CIA) because of their lower detection lunits, better precision, speed, avoidance of radioactivity, and ease of automation. Most laboratories in the United States measure AFP by use of automated systems available from Abbott Laboratories (Abbott Park, 111,), Bayer (Medfield, Mass.), Beckman Coulter (Fullerton, Calif.), Diagnostic Products (Los Angeles), and Perkin Elmer (Norwalk, Conn.). Judging from the results of proficiency testing sponsored by the Foundation for Blood Research and College of American Pathologists (Survey FP), all of these systems perform satisfactorily. ... 

The ELISA and EIA receptor systems measure substances at concentrations as low as a few nanograms (10 g). This sensitivity is not sufficient for detecting many substances and alternate methods have been devised. One is chemiluminescence immunoassay (CLIA), which can measure concentrations in femtogram (10 g) quantities. CLIA depends on the detection of emitted light associated with the dissipation of energy from a substance... 

Fu, Z., Hao, C., Fei, X., and Ju, H. (2006) Flow injection chemiluminescent immunoassay for alpha fetoprotein based on epoxysilane modified glass microbeads. Journal of Immunological Methods, 312, 61 67. 

Leonard, H. Campbell, J. Malliaros, D. Berg, M. Houser, S. McLaughlin, L. Comparison of a theophylline HPLC reference method with an automated chemiluminescent immunoassay (Abstract 122). Ther.DrugMon.it., 1995, 17, 413... 

Only limited development of new methodologies has taken place for immunochemical analysis of nucleic acids. Most published methods rely on modifications to classical DNA probe hybridization or immunoassay methods, with considerable blending of the two. For example, some methods employ immobilized oligonucleotide probes to capture the analyte DNA followed by immunoenzymatic detection. Other methods use immunocapture followed by detection with an enzyme-labeled DNA probe. Distinctly new methodologies mostly impact on assay formats (e.g., DNA microarrays and in situ hybridization) and detection reagents (e.g., chemiluminescent enzyme substrates). 

LC—MS/MS assays for 25-OHD [27] are now commonplace in clinical laboratories, especially larger reference laboratories. Often, the first step in the analysis is a liquid—liquid extraction of nonpolar 25-OHD and a deuterated internal standard from serum into an organic solvent, followed by evaporative concentration and injection into the LC—MS/MS. Additional reported metirods for specimen preparation include manual and online solid-phase extraction and simple protein precipitation with an organic solvent. The advantages of LC—MS/MS assays over traditional radioimmimoassays and more current chemiluminescent immunoassays include the use of an isotope dilution for precise quantitation, as well as the ability to distinguish and separately quantitate 25-hydroxy vitamin D2 and 25-hydroxy vitamin D3. There is considerable controversy as to which method of 25-OHD quantitation is the best, however, since many large scale population studies on vitamin D, such as the Women s Health Initiative (WHl) and the National Health and Nutrition Examination Survey (NHANES), utilized radioimmunoassays [28]. 

The high specifity of antigen-antibody reactions, and the sensitivity of these reactions, combined with the equally high sensitivity of chemi- and bioluminescence reactions, have led to the development of methods of chemiluminescent immunoassays, as an alternative to the commonly used radioimmunoassay [119]. 

Two general methods are available at present for chemiluminescent immunoassay, in which the antigen is labeled by a component of a chemi- or bioluminescent system ... 

It is unnecessary to provide further detail of the apparatus since some excellent descriptions are in the literature [14-20]. These allow the construction of simple and hence flexible systems, yet thoroughly examine the theory of hght measurement so that the investigator can choose the most suitable apparatus. With the growth of interest in luminescence-based immunoassay methods, there has been a rush by many manufacturers to produce luminometers to serve this potentially lucrative market. The instruments and the addresses of the companies are listed in reference 2. It is important to point out however, that these instruments are rarely suitable for research work in the field of chemiluminescence itself. They are sensitive and where the analytical requirements are well defined, they can be very convenient. More flexibility is required in the apparatus used for investigations of the fundamental light reaction and its mechanism. 

The biological and medical sciences are ripe for iastmmentation advances. Whereas most immunoassays (qv) use radioactive materials, the implementation of chemiluminescent methods, enzyme techniques, and electrochemical methods is expected to become more important. New and better noninvasive methods of iavestigation are expected to become more routine. In addition, real-time measurements, whereby analyses of a number of... 

Oxidative stress Lipid oxidation Oxygen absorption Manometric, polarographic Diene conjugation HPLC, spectrophotometry (234 nm) Lipid hydroperoxides HPLC, GC-MS, chemiluminescence, spectrophotometry Iodine liberation Titration Thiocyanate Spectrophotometry (500 nm) Hydrocarbons GC Cytotoxic aldehydes LPO-586, HPLC, GC, GC-MS Hexanal and related end products Sensory, physicochemical, Cu(II) induction method, GC TBARS Spectrophotometry (532-535 nm), HPLC Rancimat Conductivity F2-iP GC/MS, HPLC/MS, immunoassays... 

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