Immunofluorescence mapping is based on the detection of structural proteins of keratinocytes or of the dermo-epidermal junction using specific poly- or monoclonal antibodies. Through this method, the level of split formation can be determined by investigating the location of a given antigen in a natural or induced blister. This method also allows testing for the normal expression, reduction or absence of various structural proteins depending on the antibodies used. It has widely replaced transmission electron microscopy and is used as the initial laboratory test to prove the clinical diagnosis of epidermolysis bullosa.