In chemistry and medicine, protein electrophoresis (a.k.a. Immunoelectrophoresis) is a method of analysing a mixture of proteins by means of gel electrophoresis, mainly in blood serum (blood plasma is not suitable). Before the widespread use of electrophoresis gels, protein electrophoresis was performed on paper (sometimes in combination with paper chromotography).
There are two classes of blood proteins: serum albumin and globulin. They are generally equal in proportion, but albumin is much smaller and lightly negatively charged, leading to an accumulation of albumin on the electrophoretic gel. A small band before albumin represents transthyretin (also named prealbumin). Some forms of medication or body chemicals can cause their own band, usually small. Abnormal bands (spikes) are seen in monoclonal gammopathy of undetermined significance and multiple myeloma, and are useful in the diagnosis of these conditions.
The globulins are classified by their banding pattern (with their main representatives):