Guest guest Posted August 5, 2009 Report Share Posted August 5, 2009 Lyme and the tale of two tests Diagnosing The Disease; As ticks spread into Canada, concern rises about rigour of existing screenings. Lia Grainger, National Post Published: Wednesday, August 05, 2009 _http://www.nationalpost.com/related/links/story.html?id=1860023_ (http://www.nationalpost.com/related/links/story.html?id=1860023) When Jim Wilson was finally diagnosed with Lyme disease, he was baffled. Now the head of the Canadian Lyme Disease Foundation, Wilson had been sick for years and the medical community had been stumped as to the cause of his illness. On hearing his diagnosis, his first thought was, **Why did the doctors not even consider Lyme disease over the previous four years?** The answer to that question lies with the guidelines used by medical practitioners to diagnose and treat the controversial disease that is now reported to be spreading in Canada. These guidelines are set in Canada by the Canadian Public Health Laboratory Network (CPHLN) and in the United States by the Infectious Disease Society of America (IDSA). Advocates for the treatment of chronic Lyme disease believe the guidelines that dominate popular and expert opinion on Lyme disease in North America have caused many infected patients to go undiagnosed and untreated. Doctors and researchers who set the guidelines disagree and believe changes to the guidelines could lead to misdiagnoses and to the misuse of antibiotics on patients who do not have Lyme disease. Both the U. S. and Canadian guidelines advocate a two-tiered testing system that requires a positive screening test, called an ELISA or EIA test, before proceeding to a Western blot test. Lyme disease advocates such as Dr. Ernie Murakami of British Columbia believe it is this system that is leading to thousands of missed diagnoses a year. " It should be based on a clinical diagnosis, " Murakami says. " These tests are notorious for turning out false negative results. " Dr. Muhammad Morshed is a clinical microbiologist at the University of British Columbia. He contributed to both guidelines, and sees no need for a revision. " From a laboratory point of view, I don't think we need to alter anything, " Morshed says. " We can always adjust it if we find out more information, but the two-tiered system --a screening with a sensitive test followed by a very specific complementary test -- stands in a good way from a laboratory point of view. " Most Lyme disease advocates believe that the Western blot test produces more accurate results, and many Canadian patients who believe they may have Lyme disease pay private laboratories in the U. S. to give them this test. Dr. Nicholas Ogden is an expert in tick-borne diseases at the Universite de Montreal in Quebec and a researcher at the Public Health Agency of Canada, and he encourages patients to be cautious when sending blood to be tested by commercial laboratories in the U. S. He says for-profit laboratories may be using unproven interpretations of tests that are themselves recognized, like the Western blot test. " It's an issue that does potentially muddy the waters, " Ogden says. " They may be using very loose interpretations of test results. " Both guidelines also advise testing only if the patient has been exposed to a known endemic area during tick season, but a recent study headed by Ogden and co-authored by Morshed reveals that the endemic areas in Canada are more widespread than previously believed, and will continue to grow as global warming creates an environment increasingly hospitable to ticks. Once believed to be contained to a small area of Lake Erie's shoreline in Ontario, the report says that Lyme disease has now been identified in southern Ontario, Nova Scotia, southeastern Manitoba, New Brunswick and southern British Columbia. The report also warns of a low risk of contracting the disease outside of endemic areas from ticks that have fallen off migratory birds. Perhaps most concerning to advocates on both sides of the border, though, has been the virtual dismissal in the U. S. guidelines of the very existence of chronic Lyme disease. The U. S. guidelines currently state: **Unfortunately, it is apparent that the term *chronic Lyme disease* is also being applied to patients with vague, undiagnosed complaints who have never had Lyme disease ... the majority of patients [who believe they have chronic Lyme disease] have had no convincing evidence of ever having had Lyme disease, on the basis of the absence of objective clinical, microbiologic or serologic evidence of past or present.** Since their publication, these findings have been called into question. In May 2008, Richard Blumenthal, the Attorney General of Connecticut, began an investigation of the IDSA*s 2006 guidelines, based on allegations that **the IDSA's guideline panel improperly ignored or minimized consideration of alternative medical opinion and evidence regarding chronic Lyme disease, potentially raising serious questions about whether the recommendations reflected all relevant science.** Blumenthal also reported that members of the IDSA panel **undercut its credibility by allowing individuals with financial interests --in drug companies, Lyme disease diagnostic tests, patents and consulting arrangements with insurance companies -- to exclude divergent medical evidence and opinion.** The IDSA denied all of Blumenthal's findings and negotiated an end to the investigation by agreeing to form an entirely new panel monitored by the office of the Attorney General to review the guidelines. That review commenced with a hearing last Thursday, and the panel says it hopes to publish its findings by the end of this year. Though Canada operates under its own guidelines, they are similar to those set by the IDSA that are currently under review. The continued discord over the very existence of chronic Lyme disease in the U. S. coupled with the reported spread to new previously unaffected areas of Canada seems likely to increase the visibility of the issue on both sides of the border in the coming months. For the time being, there have been no announcements of plans to alter the Canadian guidelines, though both Morshed and Ogden say new findings could lead to changes. " We're not sitting idly by and saying these are the best tests and we're not doing anything about it, " Ogden says. " We know they're not perfect. " - For updates on ticks and what to do if you're bit, visit Health Canada at hc-sc. gc.ca. _lgrainger_ (lgrainger) Previous article: (http://www.nationalpost.com/life/health/story.html?id=1862262) Debate over Lyme disease lingers on, with a U.S. twist Lia Grainger, National Post Published: Wednesday, August 05, 2009 _http://www.nationalpost.com/life/health/story.html?id=1862262_ (http://www.nationalpost.com/life/health/story.html?id=1862262) Quote Link to comment Share on other sites More sharing options...
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