Immunodermatology testing is essential for the correct diagnosis and treatment of several diseases affecting epithelial organs, especially skin and mucous membranes. The various diseases often overlap in clinical and histological presentation and, although the diseases themselves are not common, may present with features of common skin disorders such as urticaria, eczema and chronic itch. Therefore, the diagnosis of an immunodermatological disease is often delayed. Immunodermatology testing encompasses identification of immunological patterns on biopsy specimens and in serum. Direct immunofluorescence is performed on perilesional skin for blistering disorders and on lesional skin for connective tissue diseases and vasculitis. Serum testing by indirect immunofluorescence and enzyme linked immunosorbent assay (ELISA) is critical in confirming a diagnosis and in differentiating among immunobullous disorders and subtypes. Serum testing can be helpful for diagnosis when it is not practical to obtain a biopsy specimen. Serum antibody profiles and levels are useful in monitoring disease expression and response to therapy.