Radial immunodiffusion immunoassay

Cost Effectiveness. As with the other advantages of immunochemical analysis, cost may be quite variable. Reagent costs for several automated systems have been estimated at under 1.25 per sample. The cost is obviously much lower for less sophisticated assay systems, especially if some reagents are prepared in house. A major consideration is the expense of new instrumentation. For dedicated or automated instrumentation for either RIA or ELISA procedures, the cost may be 50-100,000. However, most analytical laboratories already have the basic instrumentation needed for immunoassays. Moderate sensitivity can be obtained through the use of numerous procedures such as radial immunodiffusion and hemagglutination. These procedures require no expensive equipment or reagents and they may be very useful in areas where equipment acquisition or maintenance is a problem. 

Although it is possible to estimate apoC concentrations in lipoprotein fractions by delipidation, electrophoresis or isoelectric focusing, staining, and densitometry [e.g., (C5, N3)], or by high-pressure liquid chromatography (H6), most reported measurements of plasma apoC concentration have been by immunological means. These include radioimmunoassay (K8, K9, S17), electroimmunoassay (A4, A5, C27), radial immunodiffusion (P21), and enzyme immunoassay (H29). 

Immunochemical methods are also used for clinical assays because they are rapid and easily automated. Because of the differences in molecular size and corresponding diffusion rates, gel diffusion techniques, such as radial immunodiffusion (RID) require correction for phenotype and are therefore time consuming and inconvenient. Immunoassays in solution, such as nephelometry and turbidimetry, are influenced slightly by size as well, but the differences are relatively insignificant. 

Apolipoproteins are measured by a wide variety of immunoassays, including radioimmunoassay (RIA), ELISA, radial immunodiffusion (RID), immunoturbidimetric assay, and immunonephelometric assay. The concentration of a particular apoHpoprotein usually determines the immunotechnique used for its measurement. 

Many different immunoassays can be used for the quantification of immunoglobulin isotypes and subclasses, varying from ELISA/ FEIA and radial immunodiffusion (RID) to nephelometry/turbid-imetry (Rose et al., 2002). The immunoglobulin isotypes IgA, IgG, and IgM in particular are present in relatively high concentrations in the circulation (0.5-20 g/l). These isotypes are often quantified by... 

ABEI produces ECL when oxidized at 1.0 V versus Ag/AgCl in alkaline aqueous solution. In contrast to luminol, ABEI labels do not markedly lose their CL efficiency when conjugated with proteins. ECL immunoassays with a flow injection analysis (FIA) system using ABEl-isothiocyanate as a label were proposed, which have a better performance than either single-radial immunodiffusion or nephelometric immunoassays. ABEI can also be used as an oligonucleotide marker to label a DNA probe. The intensity of the ABEI ECL was linearly related to the concentration of the complementary sequence in the range 96-96 nM, and the detection limit was down to 30 pM. 

Specific quantitative assay of particular proteins by immunochemical methods using specific antisera and measurement of the antigen-antibody (Ag-Ab) complexes by nephelometry, turbidimetry, radial immunodiffusion (RID) or radioimmunoassay (RIA), or enzyme immunoassay. 

Techniques for the detection or assay of various substances based on the reaction of those substances with specific antibodies (or vice versa, i.e. the detection and assay of antibodies using antigens). Such techniques include agglutination reactions, automated immune precipitation, complement fixation tests, crossed electrophoresis, counter electrophoresis, double diffusion, enzyme immunoassay, fluoroimmunoassay, haem-agglutination, immunoelectrophoresis, immunofluoresence, radial immunodiffusion, spin immunoassay, immunofixation, immunoradiometric assay and radioimmunoassay. See separate entries for these subjects. 

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