Immunofixation

Immunofixation allows to detect and specify the type of Monoclonal antibodies or immunoglobulins in serum or urine. It is of great importance for the diagnosis and monitoring of certain blood related diseases such as myeloma.

Principle

The method detects by precipitation: when a soluble antigen (Ag) is brought in contact with the corresponding antibody, precipitation occurs, which may be visible with the naked eye or with a tool.

Immunofixation permits to identify (antibodies) in a mixture in function of their specific electrophoretic mobility. For the identification antigens are used that are specific for the targeted antibody.

Specifically, immunofixation allows the detection of Monoclonal antibodies representative of diseases such as myeloma or Waldenström macroglobulinemia.

Technique

A plasma or a concentrated urine is deposited on a gel. With an electrical current the proteins are sorted in function of their size, after which antigens for each targeted type of immunoglobulin are deposited on the gel. Thus more or less narrow bands appear on the gel, marking the location of the various immunoglobulines.

Immunofixation tends to replace Protein electrophoresis because :
* it is faster (results within three hours) ;
* it is somewhat more sensitive. Immunofixation may reveal an immunoglobulin missed out by Protein electrophoresis, especially at low concentrations (less than 1 gram/litre) ;
* it can be partially automated and can be used in more laboratories;
* it is more easily read and interpreted.

Immunofixation is however only sensitive to immunoglobulins and is more expensive than Protein electrophoresis.

ource

*

ee also

* Immunoelectrophoresis

External links

* - "Immunofixation - serum"
* - "Immunofixation - urine"
* [http://path.upmc.edu/cases/case69/serum.html Diagram] at University of Pittsburgh School of Medicine