Molecular biology and immunology for clinicians

Electrophoresis is a technique that allows the separation of charged molecules within a mixture into individual components. This represents a very powerful tool in research but has come into its own as a component of serologic testing. Western (immuno-) blot analysis takes advantage of the protein separation accomplished by a particular type of electrophoresis, called sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), to identify antibodies to individual components of cells, be they mammalian or microbial. The specificity of this kind of testing allows more rigorous testing to be done. Western blot analysis has become a "gold standard" in certain clinical circumstances and is used to corroborate equivocal or positive ELISA results in a number of diseases, Lyme disease and HIV infection being but two examples.