| Routine (zone) | The traditional clinical laboratory electrophoresis performed on a rectangle-shaped slab gel. | Separation of proteins.
Some use in separating nucleic acids. |
| High resolution (HRE) | Routine electrophoresis using a high voltage. | Conditions where more resolution of proteins is needed, eg, separation of CSF proteins for the diagnosis of multiple sclerosis and light chains in urine for early detection of lymphoproliferative disorders such as multiple myeloma. |
Polyacrylamide (PAGE)
| Horizontal or vertical slabs or gel incorporated into vertical cylinders or rods. DNA of 100 base pairs (bp) or less can be separated. | Used to study individual proteins in serum, especially genetic variants and isoenzymes (polyacrylamide gel may yield 20 or more fractions). |
| Capillary (CE) | Combines electrophoresis and high performance liquid chromatography. CE takes place in a very thin, fused silica capillary tube with polyacrylamide or agarose gel. | Commonly used in the clinical laboratory. Very rapid, efficient, easily automated, computerized, and requires only a microvolume of sample. |
| Isoelectric focusing (IEF) | The gel is infused with chemicals that make a pH gradient across the surface of the gel (ampholytes). Using very high voltage, proteins will then migrate to the point on the gel where they have no net charge, ie, their isoelectric point.
| Separation of variant hemoglobins in prenatal screening and isoenzymes. Detection of oligoclonal bands in gamma-globulin. |
| Immunofixation | An agarose gel electrophoresis separates the proteins in a serum sample. Antiserum against the protein of interest is spread directly on the gel. The protein of interest precipitates in the gel matrix. After a wash step to remove other proteins, the precipitated protein is stained. | Study protein antigens and their split products. Identify proteins found in multiple myeloma. |
| Pulsed field | Fragment separation is achieved by alternately applying the power to different pairs of electrodes. The most common method alternates the positive and negative electrodes in cycles during electrophoresis | Separates larger fragments of DNA (> 50 kilobases) that cannot be separated with AGE or PAGE in routine electrophoresis systems.
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| Two-Dimensional | Separating the same sample with two distinct separation techniques or two different electrophoresis separations. The separated bands from one electrophoresis are resolved more with the second electrophoresis. IEF followed by PAGE or AGE is the most frequent two-dimensional electrophoresis. The gel from the IEF capillary is removed and placed across the PAGE or AGE gel slab at right angles for the second electrophoresis. | Most applications are in research fields. Used to study families of proteins in the field of proteomics and protein content in different types of cells. Used in genetics to study differences in diseases, gene mutations, and bacterial DNA. Used to study tumor cells to detect malignancies. |
