Immunofluorescence

Specimen:

Lesion or organ biopsy eg, skin, kidney, lung; must be fresh, unfixed and delivered immediately to the laboratory. 

Immunofluorescence transport medium can be used if the laboratory is distant or delivery is delayed. 

Consult laboratory staff prior to obtaining and sending the specimen to ensure optimal sampling and processing conditions. 

In special circumstances, antigen retrieval can be used for immunofluorescence of fixed tissue. 

The results of this are, however, often unsatisfactory as there are problems with reliability, sensitivity and altered staining patterns.

Method:

Direct immunofluorescence.

Application:

Detection of immunoglobulin and complement deposition, especially in renal and skin biopsies.  Detection of viral or bacterial antigens eg, cytomegalovirus, mycobacteria, legionella. 

Interpretation:

Positive staining indicates the presence of the antigen. 

The pattern and localisation of staining is an aid in the diagnosis of some bullous and inflammatory skin diseases and immune complex and antibody-mediated renal diseases. 

Detection of viral and bacterial antigens confirms the presence of a specific infection.

Reference:

Taylor CR and Cote RJ. Immunomicroscopy: A diagnostic tool for the Surgical Pathologist. Volume 19 in the major problems in pathology series. 3rd ed. 2005.  Elsevier Saunders.