Inter-laboratory validation of an ELISA for the determination of serum anti-ganglioside antibodies

Anti-ganglioside antibodies are frequently sought in the sera of patients w ith autoimmune peripheral neuropathy; using an enzyme-linked immunosorbent assay (ELISA) as the principal method for antibody detection Wide variation s in assay performance between laboratories have been reported. In this stu dy, we established a standardized ELISA method between laboratories within the European Inflammatory Neuropathy Cause and Treatment (INCAT) group and determined the inter-laboratory variance in assay performance using both th e standardized INCAT method and in-house local methods. As expected, the in ter-laboratory variances were greater using local methods than using the st andardized method, producing titre estimates which could be 24.8 or 7.6 tim es Larger or smaller, respectively, than the true means for these laborator ies. Using the standardized method, the within laboratory measurement error accounted for 41% of the inter-laboratory variation, providing a theoretic al upper Limit to which technical improvements within laboratories could re duce inter-laboratory variation. These data describe the intrinsic weakness es within the widely used ganglioside antibody ELISA methods and reinforce the importance of inter-laboratory cooperation within this area. Standardiz ed serological reagents used in this study are available from INCAT members . Eur J Neurol 6:71-77 (C) 1999 Lippincott Williams & Wilkins.