A 35-year-old man with a positive Lyme test result from a private laboratory

This fictional practice case scenario needs to have some modicum of realism if it is intended to be useful to inform diagnostic and treatment decisions. The patient, who believes he could have Lyme disease and felt compelled to pay out-of-pocket for more potentially informative testing than is available in Canada, would most likely have an extensive list of multi-systemic symptoms, not just one (i.e. fatigue).(1)

He might have shown his primary care provider a rash one year before, but had been told that it looked like a bruise, ringworm, a "spider" bite or cellulitis. Erythema migrans lesions can be highly variable. Unfortunately, many articles (like this one) that continue to promote the misconception that EM rashes are always of "bull's-eye" form are still being accepted for publication when, in fact, a target shaped lesion is a relatively uncommon presentation (less than 20%). (2, 3)

The patient probably saw many physicians over the year, but likely none would have evaluated the full panoply of his migrating and/or cyclical symptoms, been cognizant of expanding local and global epidemiological risk for Lyme, considered tick-borne diseases in the differential diagnosis, or known what relevant questions to ask.

Patients are very aware that Lyme serology performed in Canada has important limitations to its reliability. (4) Testing in Canada (aside from "European Lyme" IgG WB, available from the NML) is based on antibody reactivity to a single laboratory grown strain of a single species of Borrelia burgdorferi. Research has shown our testing will not reliably identify all of the species and strains of Borrelia a patient might be infected with here or abroad. (5, 6, 7)

Health Canada has advised, "Serologic test results should be used to support a clinical diagnosis of Lyme disease and should not be the primary basis for making diagnostic or treatment decisions."(4) In light of the many limitations to the reliability of Lyme serology and in keeping with the diagnosis of numerous serious diseases and medical conditions that are made based on symptom presentation, physical findings and epidemiological risk without requiring a positive antibody test it seems unreasonable and misguided to insist on positive serology in post-acute stages of Lyme disease.

Improved diagnostic guidance, tools and specialized clinical training are needed to provide physicians with the knowledge, expertise and the confidence to use their own judgement in determining accurate diagnoses and whether empirical treatment would be appropriate for a particular individual.

1. Maloney, EL. The Need for Clinical Judgment in the Diagnosis and Treatment of Lyme Disease. Journal of American Physicians and Surgeons. Volume 14, Number 84-3. Fall 2009. Available from: http://www.jpands.org/vol14no3/maloney.pdf

2. Aucott J, Morrison C, Munoz B, Rowe PC, Schwarzwalder A, West SK. Diagnostic challenges of early Lyme disease: Lessons from a community case series. BMC Infectious Diseases. 2009;9:79. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2698836/

3. Lyme MD poster final 3 - PHPA. Available from: http://phpa.dhmh.maryland.gov/OIDEOR/CZVBD/Shared%20Documents/Lyme_MD_poster_FINAL.pdf

4. Health Canada. Canadian Adverse Reaction Newsletter, Volume 22 - Issue 4 - October 2012. Available from: http://www.hc-sc.gc.ca/dhp-mps/medeff/bulletin/carn- bcei_v22n4-eng.php

5. Wormser GP, Liveris D, et al. Effect of Borrelia burgdorferi Genotype on the Sensitivity of C6 and 2-Tier Testing in North American Patients with Culture-Confirmed Lyme Disease. Clin Infect Dis. 2008; 47 (7): 910-914. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773679/

6. Ivanova L, Christova I, Neves V, et al. Comprehensive Seroprofiling of Sixteen B. burgdorferi OspC: Implications for Lyme Disease Diagnostics Design. Clinical immunology. 2009;132(3):393-400. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2752154/

7. Krause PJ, Fish D, Narasimhan S, and Barbour AG. Borrelia miyamotoi infection in nature and in humans, Clinical Microbiology and Infection. July 2015; Volume 21, Issue 7: 631-639. Available from: http://www.clinicalmicrobiologyandinfection.com/article/S1198- 743X%2815%2900294-3/fulltext

Conflict of Interest:

None declared