Questioning the specificity and sensitivity of ELISA for bullous pemphigoid diagnosis

The reported sensitivity and specificity of enzyme-linked immunosorbent assay (ELISA) for bullous pemphigoid (BP) diagnosis is approximately 87% and 98%, respectively. These statistics suggest that ELISA is a reliable diagnostic test; therefore, the use of ELISA for BP diagnosis has increased. We report the case of a man who was diagnosed with BP and was treated for 3 years based on a positive ELISA for IgG against BP180. After reevaluation, his revised diagnosis was not consistent with BP based on clinical presentation, histopathology, and direct immunofluorescence (DIF). Reviewing reports of ELISA for BP diagnosis in the literature revealed several issues including dissimilar diagnostic procedures and patient populations, multiple reports of positive ELISA in patients without BP, and lack of explanation for these false-positives. This case report and review of the literature is a cautionary tale regarding the use of ELISA as an independently reliable test for BP diagnosis.