Detection of M2 antimitochondrial antibodies by dot blot assay is more specific than by enzyme linked immunosorbent assay

Aims: The objective of our study was, in one hand, to determine the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ELISA and dot blot assay to investigate IgG M2 antimitochondrial antibodies (M2 AMA) and, on the other hand, to compare these results with those of indirect immunofluorescence technique (IIF). Methods: Sera from patients suffering from primary biliary cirrhosis (PBC) (n = 55), systemic lupus erythematosus (n = 21), celiac disease (n = 30) and blood donors (n = 75) were analyzed. M2 AMA were detected by ELISA and dot blot using pyruvate dehydrogenase purified from porcine heart and by IIF on cryostat sections of rat liver-kidney-stomach. Results: IIF was more sensitive (98%) than ELISA (93%) and dot blot (91%). The specificity of AMA for PBC using IIF, ELISA and dot blot reached 100%, 92% and 100%, respectively. The PPV of IIF, ELISA and dot blot was 100%, 93% and 100%, respectively. The NPV was 98% for IIF, 92% for ELISA and 91% for dot blot. Conclusion: Dot blot, using purified pyruvate dehydrogenase, had a higher specificity than ELISA and may be useful in confirming the specificity of AMA in cases of doubt with IIF. © 2007 Elsevier Masson SAS. All rights reserved.