RECOMMENDATION TO INCLUDE OSPA AND OSPB IN THE NEW IMMUNOBLOTTING CRITERIA FOR SERODIAGNOSIS OF LYME-DISEASE

In October 1994, the Second National Conference on the Serologic Diagn osis of Lyme Disease recommended a two-step approach to serological te sting. The first step was the performance of an enzyme-linked immunoso rbent assay (ELISA); the second step was a confirmatory immunoblot. Ne w criteria for the interpretation of a positive immunoblot were also r ecommended. The committee decided to omit the 31- and 34-kDa bands (Os pA and OspB, respectively) from the choice of bands considered diagnos tic for a positive immunoblot, Since we had previously included these in our diagnostic criteria for Lyme disease-positive immunoblots, we r eviewed data for all patients attending a Lyme disease center with pos itive ELISAs and immunoblot assays for Lyme disease from 1 September 1 992 to 31 December 1993. The criteria for a positive Western blot (imm unoblot) were the presence of 5 of 12 bands, including the 10 recommen ded by the conference, and the presence of the 31- and 34-kDa protein bands. Of the 136 patients evaluated, 50 were considered to have Lyme disease. Of these 50, 4 (8%) would not have met immunoblot criteria fo r the diagnosis if the new recommendations were used. Had the 31- and 34-kDa bands been included as part of the diagnostic requirements for immunoblot, these patients would have been included. Although overdiag nosis of Lyme disease appears to be the more frequent problem, our con cern is that the exclusion of the 31- and 34-kDa protein bands from th e diagnostic criteria may result in the underdiagnosis of Lyme disease by those who would rely too heavily on serological confirmation. The addition of the 31- and 34-kDa bands to those recommended for confirma tory immunoblot should be reconsidered.