Validation of the BIOCHIP test for the diagnosis of bullous pemphigoid, pemphigus vulgaris and pemphigus foliaceus

Background The BIOCHIP is a novel multiplex indirect immunofluorescence technique used in the serological diagnosis of bullous pemphigoid and pemphigus. The BIOCHIP method combines the screening of autoantibodies and target antigen‐specific substrates in a single miniature incubation field. Objective To evaluate the diagnostic accuracy of the new immunofluorescence BIOCHIP multiplex tool in pemphigus and bullous pemphigoid. Methods For the validation of the BIOCHIP , sera from patients with BP ( n  = 38), PF ( n  = 8) and pemphigus vulgaris ( PV ) ( n  = 23) were used. In addition, sera from disease control patients ( n  = 63) and healthy volunteers ( n  = 39) were used. The multiplex BIOCHIP and direct immunofluorescence ( DIF ) were performed for all BP , PF and PV patients. Additional indirect immunofluorescence (IIF) was performed on patients with BP , and ELISA was performed on patients with pemphigus. Results The BIOCHIP mosaic showed a sensitivity of 86.8% and specificity of 85% for BP 180 or BP 230 being positive in BP . It demonstrated a sensitivity of 75% and specificity of 97.7% for Dsg1 in PF . The BIOCHIP was found to have a sensitivity of 60.9% and specificity of 73.6% for Dsg3 in PV . Conclusion The BIOCHIP mosaic‐based immunofluorescence test is potentially a simple, time and effort saving test that can aid in the diagnosis and screening of BP , PV and PF . However, there is potential for interpretation bias and a learning curve that needs to be taken into consideration.