ELISA Negative but Western Blot Positive?

Has anyone personally run into this particular paradox in their Bb diagnostics testing?

yep - in fact one of the criticisms of the standard Two tiered test method for lyme - that uses C6 Elisa first and then the western Blot second, is that its the reverse of the logic normally used in two tier testing for other diseases

in that - its normally the case that the most sensitive of the two tests is used first - followed by the more specific test second - the normal logic is that otherwise you will artificially exclude true positives in the first stage

but for lyme the wester blot/ immunoblot is the more sensitive test ( detects a higher percentage of infected persons ) and the C6 ELISA is most specific - but least sensitive - so the method is the reverse of the norm.

anyway - the C6 ELISA is more specific ( true positives are likely to be true positives ) but least sensitive ( false negatives are common)

the manufacturers often claim above 90% sensitivity and specificity for their lyme tests
(one reason my be that its actually hard to sell a test that declares accuracy lower than this )
but many independent estimates put the sensitivity of the C6 ELISA at around 20-30%
and the Western Blot/immuno blot at more like 40-60%

summary of papers on two tier testing accuracy
VIEW IMAGE

when i did a deep dive into lyme testing i found peer review papers that showed the outer surface proteins of in many species of borrelia that cause lyme disease differed from the borrelia burgdorferi B31 strain that the C6 ELISA is based on

this means that although the manufacturers claim this test is accurate for all the main species that cause lyme disease - independent research appears to show the more common species in Europe - B. Alfzelli and B. Garinnii - and presumably other species around the world, do not share the same outer surface protein sequence as the B31 strain - and therefore would not be expected to cause the host to be positive for the C6 ELISA assay.

i was negative by C6 ELISA but positive for both IgG and IgM antibodies via the Tick Plex test made by a Finish company - run at Armin - that uses antigens from B. Burgdorferi, B. Alfzelli and B. Garinnii