Immunofluroescent antibody testing is divided into Direct (performed on skin biopsy specimens) and Indirect (performed on serum). Specific antibodies react with specific tissue components. Immunoglobulins and/or complements (autoantibodies) become visible to the pathologist by reacting tissue sections of fresh and/or cryostat-frozen biopsies. The slide specimens are examined microscopically for specific immunofluorescence using a fluorescence microscope. Among other applications this technique may be used to evaluate a variety of autoimmune conditions such as lupus and arthritis.