The inventors developed a multiplex test for the detection of autoantibodies directed against five DEJ proteins (NC16A and C-terminal domain of BP180, integrin α6β4 and NC1 and NC2 domains of collagen VII) in patient/’s sera, in order to establish a specific diagnosis. The multiplex test is based on the use of microbeads coated with recombinant or purified DEJ proteins, which can be analyzed by flow cytometry or Luminex® technology. The multiplex test allows the simultaneous measurement of multiple autoantibodies in a single sample, reducing the cost, time, and volume of serum required. The multiplex test also has the potential to improve the sensitivity and specificity of the diagnosis, as well as to provide prognostic and therapeutic information for the management of patients with autoimmune bullous diseases.