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.

The choice of ELISA-immunoblot combination severely influences the number of
positive results, making the exchange of test results between laboratories
with different methodologies hazardous.