Large differences between test strategies for Lyme
By Linda on Mar 3, 2011 in Infections
Excerpt:
We investigated the influence of assay choice on the results in a two-tier
testing algorithm for the detection of anti-Borrelia antibodies.Eighty-nine serum samples from clinically well-defined patients were tested in eight
different enzyme-linked immunosorbent assay (ELISA) systems based on whole-cell
antigens, whole-cell antigens supplemented with VlsE and assays using
exclusively recombinant proteins.A subset of samples was tested in five immunoblots: one whole-cell blot, one
whole-cell blot supplemented with VlsE and three recombinant blots.The number of IgM- and/or IgG-positive ELISA results in
the group of patients suspected of Borrelia infection ranged from 34 to 59%.The percentage of positives in cross-reactivity controls ranged from 0 to 38%.
Comparison of immunoblots yielded large differences in inter-test agreement and
showed, at best, a moderate agreement between tests.***Remarkably, some immunoblots gave positive results in samples that had been
tested negative by all eight ELISAs.***The percentage of positive blots following a positive ELISA
result depended heavily on the choice of ELISA-immunoblot combination.We conclude that the assays used to detect anti-Borrelia antibodies have widely
divergent sensitivity and specificity.
