Re: Using IGeneX Urine Tests

a_weisman_at_yahoo.com
Date: 02/23/05 

Date: 23 Feb 2005 02:02:38 -0800

Thank you. THis information is responsive to questions raised.

It does not show independent validation of any of these claims but at
least it is responsive.

It sure doesn't make the tests out to be very sensitive though and the
specificity is less than desired.

Question: as to the 89% specificity--what causes the false positives?
How is that tested or controlled for?

Question: If the LUAT was "an art" and "very difficult to reproduce"
does Igenex dispute Klempner's findings or the validity of them when he
basically found that the test was not easily reproducible and that
results were highly variable? If so, why didn't he formally dispute
them? Why no report to NIH ORI? Why no response in American Journal of
Medicine?

Question: If the "labelled antibodies" ran out, how did he intend to
conduct a retrial of the Klempner study at his expense or anyone elses?
Why were these antibodies not clonable or otherwise reproducable?
Please give some technical details. It still sounds too glib and lacks
specifity. Where did the "labelled antibodies" come from and why were
they no longer available? How could there be a limited supply which
wasn't reproducable?

Question: If the LDA assay is more standardized and reproducible, why
not license it?

pmerv@direcway.com wrote:
> Urine Antigen
>
> The bladder has been reported as a prime site for culturing borrelia.
> This suggests that urine would be a logical place to look for
antigen.
> Some people have asked about the differences between IGeneX's
> previous urine antigen test, the LUAT and the current test urine
> antigen test, LDA (Lyme Dot Assay). According to IGeneX's President,
> Dr. Nick Harris, while both assays measure antigen, the technology is
> different.
>
> 1. LUAT was a quantitative test whereas LDA is qualitative.
> 2. The LUAT used labeled purified anti-B. burgdorferi specially
> labeled antibodies. Unfortunately, IGeneX ran out of these labeled
> antibodies. The Lyme Dot does not require specially labeled
antibodies.
> 3. The LUAT assay was an ELISA assay in which bound and free
antigen
> competed for antibody binding. The signal was read in a fluorometer.
> Although it was very sensitive, it was a complicated assay, almost an
> art; and very difficult to reproduce. Thus, some assay runs had to
be
> repeated several times. The new LDA assay is not an art and is
highly
> reproducible. It is easy to read. In LDA, the antigen present in the
> urine sample is bound to the membrane. If B. burgdorferi antigens
are
> present in the urine sample, a blue dot is visible on the membrane.
>
> The LDA assay has a sensitivity of 21%. The specificity of the LDA
is
> about 89%. Therefore, IGeneX recommends confirmation by Reverse
> Western Blot (RWB) assay. Thus, the urine antigen tests can pick up
> about 15-18% of the Lyme Disease positive patients. The LDA may also
> be present in patients positive by Lyme IgM Western Blot only. Urine
> testing can pick up about 5%-8% of patients that are negative for WB
> and blood, serum and urine PCR, which is important to the patients in
> that group.
>
> Urine PCR
>
> Bergmann et al report that by taking specific steps to optimize the
> urine PCR technique, B. burgdorferi infection can be diagnosed by
using
> urine samples from EM patients with sensitivity (85%), substantially
> better than that of serological methods (50%). IGeneX urine PCR has
> passed reviews by both New York and California. The PCR is sensitive,
> specific and reproducible because: (1) IGeneX recommends that urine
be
> collected in special preservative tubes. (2) A special method is used
> to purify and concentrate Borrelia specific DNA from a patient's
> urine sample.
>
> In summary, advantages of the urine tests are:
>
> 1. These tests are direct tests, unlike antibody tests that are
> indirect.
>
> 2. These tests can detect false negatives of the serologic
tests.
>
> 3. The test methods are non-invasive, thus suitable for all ages
> (including infants).
> 4. Unlike antibody tests, these tests can detect antigen within
few
> days of infection.
>
> You can find out more at the IGeneX website.
>
> Phyllis Mervine, President
> California Lyme Disease Association
> Affiliate of the Lyme Disease Association, Inc.
> PO Box 1423
> Ukiah, CA 95482
>
>
> Visit our websites
> calda.intranets.com
> www.lymedisease.org
> www.lymetimes.org
> Join our online discussion and support group at
> http://health.groups.yahoo.com/group/CaliforniaLyme/

Relevant Pages

  • Re: Using IGeneX Urine Tests
    ... > This suggests that urine would be a logical place to look for antigen. ... LUAT was a quantitative test whereas LDA is qualitative. ... The LUAT assay was an ELISA assay in which bound and free antigen ... If B. burgdorferi antigens are ...
    (sci.med.diseases.lyme)
  • Using IGeneX Urine Tests
    ... This suggests that urine would be a logical place to look for antigen. ... LUAT was a quantitative test whereas LDA is qualitative. ... The LUAT assay was an ELISA assay in which bound and free antigen ... If B. burgdorferi antigens are ...
    (sci.med.diseases.lyme)
  • Re: Using IGeneX Urine Tests
    ... >> Urine Antigen ... If B. burgdorferi antigens ... >> and blood, serum and urine PCR, which is important to the patients ... >> Affiliate of the Lyme Disease Association, ...
    (sci.med.diseases.lyme)