Automated immunochemical method

Immunochemical methods, especially automated immunoturbidimetry and immunonephelometry, are more accurate and precise than the methods mentioned previously. 

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. 

The future use of coated piezoelectric devices as immunochemical sensors, even directly in the liquid phase, is very promising and could be considered a very competitive alternative to other types of immunoassay. Only this technique and that of surface plasmon resonance provide labelless methods for the direct study of antigen-antibody reactions, and their analytical possibilities. The devices can be easily automated or combined with flow injection systems, extending their capability of continuous and repeated assays. This raises an exciting possibility of using crystal arrays to assay for different analytes in complex samples with an on-line display of the results. 

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