Lyme Testing Gets Fast and Easy

This transcript has been edited for clarity.

Hello. I'm Paul Auwaerter with Medscape Infectious Diseases, speaking from the Johns Hopkins University School of Medicine.

Lyme disease serologic testing has often been a difficult issue for clinicians and patients alike, both in receiving testing results on a speedy basis and dealing with the confusing presence of bands and trying to interpret what it all means.

The US Food and Drug Administration has recently approved a modified two-tier approach, whereby two enzyme immunoassays (EIAs) alone are necessary instead of the current standard (which has existed for 25 years), where a first-tier EIA is followed by an immunoblot or Western blot.^[1]

This modified approach, which relies on two easy-to-run tests, offers several advantages. When the test was examined for both early Lyme disease and later noncutaneous Lyme disease, it performed as well—if not a bit better—in detecting identifiable antibodies against Borrelia burgdorferi, the causative agent of Lyme disease.^[2,3]

Laboratory pathologists would very much like to do away with the immunoblot components of Lyme disease testing because they are fraught with difficulties, both technical and in interpretation, whereas EIAs are much easier to run in the laboratory, provide quicker results, and may be less expensive.^[4]

Instead of waiting for immunoblot testing, it's quite possible that you will get these test results back quicker with a positive, equivocal, or negative result, and you could therefore confirm whether someone has Lyme disease. However, you still run into trouble with the same IgM positivity, so you should ask your laboratory if they are running independent IgM and IgG confirmatory testing.

These advantages outweigh those of the current approach. The standard two-tier approach will still be there if needed and is offered as an alternative to this modified two-tier testing.

This modified approach also offers advantages in terms of helping clinicians and patients get to treatment earlier, and it seems to be as accurate as the standard approach—both sensitive and specific—based on assessment in a large number of specimens that have been clinically verified.^[3]

This has been a long time coming. We are still looking for even more improvements in testing because these antibodies don't necessarily reflect active infection and can reflect past infection. There are needs for improvement in diagnostic testing for Lyme disease in the very earliest phases of infection that don't depend on antibodies, especially for patients without the characteristic erythema migrans rash.

Tests that track with microbiologic cure would be very reassuring to people, especially if there are concerns that they don't improve after initial testing. If a patient is not improving, you should determine whether you have an accurate diagnosis of Lyme disease.

My sense is that this approach works as well, if not better, for early Lyme disease detection. You can have confidence that the modified approach will also detect Lyme disease for patients who might have later neurologic presentations. Thanks very much for listening.

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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Cite this: Paul G. Auwaerter. Lyme Testing Gets Fast and Easy - Medscape - Sep 13, 2019.

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