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CDC's Advice re LD Testing: Follow the Steps

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CDC's Advice re LD Testing: Follow the Steps

Postby RitaA » Wed 7 Mar 2012 1:35

http://www.medscape.com/viewarticle/758995

(You'll need a valid ID and password to access the article online)

From CDC Expert Commentary

Testing for Lyme Disease: Follow the Steps

Barbara J.B. Johnson, PhD

Authors and Disclosures

Posted: 03/05/2012

Hello, I am Dr. Barbara Johnson. I am a microbiologist with the Centers for Disease Control and Prevention, and I am pleased to speak with you today as part of the CDC Expert Commentary Series on Medscape about serologic testing for Lyme disease. Serology is currently the only type of diagnostic test for Lyme disease approved by the US Food and Drug Administration.

Serologic tests are designed to detect antibodies that the immune system makes in response to an infectious organism, in this case the spirochete Borrelia burgdorferi. Before testing a patient for Lyme disease, it is important to consider the likelihood that a patient is infected. Factors to consider are:

    Symptoms: Does the patient have signs and symptoms consistent with the disease?

    Geography: Has the patient been in an area where the disease occurs?

    Behaviors: Does the patient have risk factors for exposure to ticks?

If you decide there is a reasonable chance that your patient has Lyme disease, serologic testing may be helpful. Remember, however, that it can take several weeks after infection for a serologic test to become positive. This means that patients with early stages of Lyme disease, such as erythema migrans, may have a negative serologic test when first seen. For this reason, it is recommended that such patients be diagnosed and treated immediately, without serologic testing. In contrast, patients who have been ill for 4 weeks or longer will almost always have antibodies, if infected. Consequently, serologic testing is very useful for diagnosing patients with later stages of disease, such as Lyme arthritis.

When testing for antibodies for Lyme disease, CDC recommends a 2-step testing process. In the first step, serum is tested using a highly sensitive but inadequately specific quantitative assay, most commonly an enzyme immunoassay, such as an ELISA. If this first test is negative, no further testing is indicated. If the first test is positive or indeterminate (also called "equivocal" or "borderline"), a second-step test should be performed.

In the second step, serum is tested by immunoblotting, either with Western or striped blots, to identify IgM and IgG antibodies against several different B. burgdorferi antigens. Some of these antigens are recognized by antibodies to other common organisms, so even uninfected patients will usually have at least 1 reactive band. The important issue is the number of bands. To be considered positive, the serum should react with at least 5 of 10 scored bands on the IgG assay and with 2 of 3 scored bands on the IgM assay.

Two important caveats:

    Do not skip steps in the 2-step process. Skipping steps, for example performing a Western blot alone, increases the chances of a false-positive result. The higher false-positive rate has ranged from 1.5%-8%, depending on the population studied.

    A positive IgM immunoblot is only meaningful during the first 4-6 weeks of illness. After that time, an infected patient should have a positive IgG immunoblot as well. If they don't, it strongly suggests that the IgM result is a false positive.

Unfortunately, there is a lot of misinformation about Lyme disease testing, most notably that the first-step tests are insensitive. This myth is based on tests that are no longer in use and inappropriately expecting positive results for patients who are in the early stages of infection, for whom serologic testing is not recommended. In truth, first-tier tests for Lyme disease are quite sensitive -- sensitive enough to react in some patients with other spirochetal diseases, such as tick-borne relapsing fever, syphilis, or leptospirosis, as well as with other infectious and noninfectious conditions.

For more information about Lyme disease, the geographic areas of risk, and appropriate laboratory testing procedures, please consult the CDC Website list below. Thank you.

Web Resources

Aguero-Rosenfeld ME, Wang G, Schwartz I, Wormser GP. Diagnosis of Lyme borreliosis. Clin Microbiol Rev. 2005;18:484-509.

CDC. Lyme Disease

CDC. Lyme Disease: Laboratory Testing

CDC. Notice to readers: caution regarding testing for Lyme disease. MMWR Morb Mortal Wkly Rep. 2005;54:125.

CDC. Notice to readers: recommendations for test performance and interpretation from the Second National Conference on Serologic Diagnosis of Lyme Disease. MMWR Morb Mortal Wkly Rep.1995;44:590-591.

Wormser GP, Dattwyler RJ, Shapiro ED, et al. The clinical assessment, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2006;43:1089-1134.

United Kingdom Health Protection Agency. Diagnosis and Treatment of Lyme borreliosis.

Barbara J. B. Johnson, PhD, is a supervisory research microbiologist with the US Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, in Fort Collins, Colorado. She conducts research to improve the laboratory diagnosis of Lyme disease and other tick-borne illnesses, prevent Lyme disease by vaccination, and understand the pathogenesis of Borrelia burgdorferi infection. Dr. Johnson holds a doctoral degree in biochemistry from the University of Wisconsin, Madison.


Once again, the emphasis is on how to avoid, and deal with, false positive test results. No mention whatsoever is made about even the potential for false negative test results and any possible reasons for them.

My hypothetical question is this:

If a patient has had a known tick exposure and subsequently develops classic signs of Lyme disease, but only 4 out of the 5 required bands show up on a Western Blot IgG, where does that leave the patient and his or her doctor?

I think this question is especially difficult to answer when a physician has exercised due diligence and already ruled out other possible causes for that patient's ill health as part of a complete diagnostic work-up. Based on the CDC's stringent requirements (that were initially intended for surveillance purposes, but are now apparently also being used for diagnostic purposes), that person would NOT have Lyme disease and theoretically wouldn't qualify for any kind of treatment.

Maybe it's just me, but I think it would be entirely reasonable to treat that patient as if he or she had Lyme disease just to be on the safe side. What if -- as has been shown in a recently published European article -- that patient's antibody levels are in flux? At the very least, I think repeat testing would be warranted.

Also, does every species/strain of Borrelia react the same on a Western Blot test? Something tells me they might not. If that's the case, how is any doctor expected to recognize a potentially new/mutated strain of Lyme disease through current testing methods? I'm guessing the short answer is "They aren't".

Rita A
RitaA
 
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Re: CDC's Advice re LD Testing: Follow the Steps

Postby ChuckG » Thu 8 Mar 2012 4:51

SusanK's results.

I have left out the INDs.

IGeneX IgG
12/26/08 41 & 58
2/16/10 41 & 58
3/30/11 41 & 58
10/1/11 41

IGeneX IgM
12/26/08 18, 28, 41 & 66
2/16/10 41 & 66
3/30/11 18, 30 & 41
10/1/11 18 & 41

http://flash.lymenet.org/scripts/ultima ... c/1/114909?

Topic: Results in from Advanced Lab - Bb Direct Culture

I see the word "positive" mentioned twice.

I have been sick for 15 years - very sick past five. I am one hour into knowing I have LD.
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Location: Berkeley

Re: CDC's Advice re LD Testing: Follow the Steps

Postby Claudia » Thu 8 Mar 2012 18:50

This is of special interest to me given my son's medical and testing history: a pediatrician documented EM in July of 2001 (treatment refused unless the half-dollar sized EM expanded to over 5" to be a "true EM" or he developed swollen knees and/or flu-like symptoms over the next few weeks. This didn't happen, however the EM was visible for about a month before gradually fading and then completely disappearing. His first symptoms were neurologic, urinary dysfunction and fluctuating vision, brought to the attention of medical professionals who failed to connect the dots). Finally after becoming very ill to the point of near complete dysfunction, a late-stage CNS Lyme disease diagnosis in 2005 with an initially negative ELISA and WB. After much diagnostic testing and evaluation done at Yale, a clinical diagnosis was made, unfortunately far too long after the disease had progressed to the tertiary stage, becoming entrenched and difficult to treat. Positive Bb specific Bands began appearing on the follow up WBs during antibiotic treatment.

These are my son's WBs results from Stony Brook:

2005: IgM 41 Equivocal
IgG Negative

2006: IgM 41
IgG Negative

2007: IgM 41, 34, 39, 58, 93
IgG Negative

2008: IgM 41, 34, 39, 66, 93
IgG 41

2009: IgM 41, 34, 39, 66, 93
IgG 41

The reason my son was refused treatment when he was originally brought into his pediatrician's office with a bulls-eye rash was due to information directly provided to medical professionals like his pediatrician from the CDC and NIH and the in tandem media blitz and PR campaign by the IDSA membership in the weeks prior to his developing the rash, in response to the conclusion of the Klempner trials. I have no doubt that had my son been lucky enough to have had his EM appear in early June of 2001, instead of July of that year, his pediatrician would have erred on the side of being 'better safe than sorry' and given him a short course of generic doxycycline at the earliest stage of infection when the cure rate was near 100%. This was the same pediatrician that routinely prescribed antibiotics for my children's ear infections, sore throats, etc., during their early childhood years.

They say that luck and timing is everything in life. In my son's case with Lyme disease this was certainly true. He had the bad luck of living in Connecticut where Dr. Eugene Shapiro held a great deal of influence over pediatricians and what Lyme disease information they received and valued, and in living in a suburb outside of New York City where The New York Times newspaper is in high circulation to most households. And mostly, he had the very bad timing to have contracted Lyme disease in the footsteps of the immediate handling of the Klempner trials.

This is what his pediatrician read and then quoted to me in refusing treatment:

From The New York Times

Lyme Disease Is Hard to Catch And Easy to Halt, Study Finds
By GINA KOLATA

Published: June 13, 2001

Lyme disease is very difficult to catch, even from a deer tick in a Lyme-infested area, and can easily be stopped in its tracks with a single dose of an antibiotic, a new study shows.

And two other studies conclude that prolonged and intensive treatment with antibiotics, a course of care advocated by a small group of doctors, does nothing for people with symptoms often attributed to chronic Lyme disease. These findings are in keeping with the assertions of researchers who say that in most cases, such symptoms have nothing at all to do with the disorder.

The three studies, scheduled to be published on July 12 in The New England Journal of Medicine, were released yesterday because the journal's editors thought they were so important, with the onset of summer and the accompanying fear of Lyme disease.

''This is reassuring information for people who make decisions based on evidence,'' said Dr. Jeffrey M. Drazen, the journal's editor in chief.

Researchers, both those associated with the studies and others who were not, said they hoped the findings would ease what they called inflated public fear of Lyme disease, which is widely perceived as a grave illness that is easy to catch. A total of 16,019 cases were reported to the Centers for Disease Control and Prevention in 1999; 92 percent of those cases were in nine states, most of which are in the Northeast, including New York and Connecticut.

Dr. Leonard H. Sigal, a Lyme disease expert at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical Center in New Brunswick, who was not associated with the studies, said the message from them was that ''Lyme disease, although a problem, is not nearly as big a problem as most people think.''

''The bigger epidemic,'' Dr. Sigal said, ''is Lyme anxiety.''


The study to see whether a single dose of the antibiotic doxycycline could prevent Lyme disease was directed by Dr. Robert B. Nadelman, a professor of medicine at New York Medical College and attending physician at the Westchester Medical Center, both in Valhalla, N.Y.

Dr. Nadelman said many doctors, in hopes of heading off Lyme disease infection, had been giving 10-to-21-day courses of the antibiotic to people who had found deer ticks on their bodies.

''They would be treating people as if they actually had the disease,'' he said.

He and his colleagues wondered whether one dose would be enough. They recruited 482 people in Westchester County, N.Y., where the incidence of Lyme disease is among the highest in the world. All had found deer ticks on their bodies. (The insects were identified by entomologists.)

Half got a single dose of doxycycline, taken in the form of two capsules, and the others got two dummy capsules. The investigators found that the drug did prevent Lyme disease: just one person, 0.4 percent of those who took it, came down with the illness.

But even among those who took the placebo, the chances of getting the disease was just 3 percent.

Dr. Eugene Shapiro of Yale University School of Medicine, who wrote an accompanying editorial, noted that the antibiotic often caused nausea, vomiting and abdominal pain and that among those who took it, there would have been very little chance of getting Lyme disease in any case. People who are bitten can watch the site where the tick fed, Dr. Shapiro said, and if they develop a rash within a few weeks, they can take a full course of antibiotics.

''Give that person 10 to 21 days of antibiotics,'' he said, ''and they will be fine.''

Dr. Sigal agreed. He added that deer ticks crawl around the body for hours before settling down to feed, and during that time are easily washed off with a washcloth. And, he said, ''even if you get the disease, it is easily treatable and it is curable.''

Full article: http://www.nytimes.com/2001/06/13/us/ly ... int&src=pm



The CDC's advice regarding testing may help with the problem of the over diagnosis of Lyme disease, but directly contributes to the under diagnosis of the illness, and to the many patients whose once "easy to treat," and "rather benign" infection becomes a difficult to treat, chronic and debilitating one.

A LNE thread with additional information on the Advanced Laboratory Services Bb test "Joe Burrascano Announces New Borrelia Culture Test" viewtopic.php?f=7&t=3420
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