Laboratory Tests
By Tom Grier M.S.
Three Main Categories of Lyme Disease Tests:
1. Indirect Tests (serum antibody tests):
ELISA; Western Blot; IFA; Borreliacidal Antibody
Assay (Gunderson test);T-cell Activation Test
2. Direct detection tests:
PCR (DNA amplification); Lyme Urine Antigen Test
(LUAT); Antigen Capture Test; culturing of skin, blood,
CSF, urine, or tissue; immune complex / antigen-antibody
test
3. Tissue Biopsy and Staining:
Silver Stain; Gold Stain; Fluorescent Tagged
Monoclonal Antibody Stains; Acrodine Orange; Gram Stain;
Muramidase; etc.
There is a great deal of confusion and controversy
surrounding Lyme disease testing. The first problem is
that most of the manufacturers of these tests want you
to believe that their tests are the best. At every
medical convention, I listen to sales pitch after sales
pitch from sales people making their product sound
infallible. Often the terminology is confusing and the
customer frequently misinterprets what is really being
said.
For example, a salesman may say the rate of false
positive or false negative is less than one percent.
This sounds like the test is more than 99% accurate. In
reality, what it is saying is if you have 1000 test
samples from the same known laboratory sample, then in
less than ten samples will there be a result that
differs significantly from the other 990.
In any of this, did you hear the words: "percent
reliability" or "percent accuracy" in diagnosing Lyme
disease in humans? No! People often mistake "false
positive rate" for accuracy. The truth is that no Lyme
disease test to date is close to 100% accurate, because
each test has its own particular set of shortcomings.
So, while the first problem with Lyme disease tests is
in the way they are promoted, the second problem is the
way the tests are primed to recognize laboratory strains
of Bb, rather than wild types. Third, the Lyme
spirochete can hide in the human body, and fool the
immune system into thinking it isn't there. So, no
antibodies are produced, resulting in negative tests.
Stealth technology isn't new, it evolved millions of
years ago by the first bacteria that evaded its host's
defenses.
Immune Responses
The first antibody our body makes in response to a
foreign invader is usually immunoglobulin type M,
abbreviated as IgM. This large antibody takes two to
four weeks to be made in quantities large enough to be
consistently measured. It is at its peak of production
four weeks after exposure to an antigen. The IgM
antibody will only stay in circulation for about six
months, and then levels are usually too low to detect.
If infection persists, this antibody may also persist.
In general, a Lyme patient who consistently has
detectable IgM levels is usually chronically ill, but
its absence is not a reliable indicator of cure.
The second antibody we make after the IgM is the IgG
antibody. This antibody takes four to eight weeks to
form, and is gone in less than twelve months. It peaks
at about six weeks. This antibody crosses the placenta,
so an infected mother can pass this antibody to her
child. An IgG antibody titer in a newborn does not have
to mean active infection. It does mean the mother has
had exposure, and the child must be carefully monitored
for signs of the disease.
Because of the difference in the two antibodies, two
separate tests are available to test for their presence.
Therefore, a physician must specify whether or not a
patient should have an IgM or IgG Western Blot, or an
IgM or IgG ELISA test.
IgM:
This is the earliest of the antibodies to appear in
response to an infection. It is produced in quantity. It
is six times larger than the IgG antibody. Because of
its size, this immunoglobulin does not cross the
placenta. Since it cannot enter the fetus from the
mother, any newborn that starts to make IgM antibodies
against Lyme disease must be infected. However, a fetus
exposed to Borrelia burgdorferi early in the pregnancy
may never make an antibody response to the Lyme bacteria
because the baby's immune system doesn't recognize it as
foreign.
IgG:
This antibody remains the longest and is the foot
soldier of the immune system. It attacks viruses,
bacteria, yeast, toxins, and transplants. The IgG
antibody can kill bacteria indirectly by tagging or
marking the foreign invaders for destruction by the
killer cells (T-cells, macrophage). Or, it can kill the
bacteria directly by evoking compliment, a series of
enzymes and proteins that will dissolve the intruder.
Note: It was once thought that plasma cells could
produce antibodies that could conform to any shape
necessary to attack foreign intruders. If this were
true, we would have almost unlimited immunity. It is now
thought that each person has a finite collection of
specialized lymphocytes that are able to create a finite
number of antibodies. Each antibody shape is
predetermined, and can be produced by only one type of
lymphocyte. When the body is invaded by a foreign
antigen, it will stimulate one of these cells, and only
that cell will begin to clone itself. This process takes
several weeks. If we lack the right cell type to do the
job, we are left with a gap in our immunity. This might
account for why some Lyme patients with certain tissue
types have greater morbidity, while others have
relatively mild symptoms.
Dr. Allen Steere, M.D., observed that Lyme arthritis
patients with tissue type HLA-DR2 and HLA-DR4 had more
severe arthritis and chronic disease. Other tissue types
have been associated with an increased incidence of
multiple sclerosis and other neurological diseases. It
might be that different patient tissue types might
account for a difference in patient's symptoms to a
greater degree than different strains of the bacteria.
It is known that this bacteria has an affinity for
specific tissues. If you have a specific lack of
immunity, this may cause the disease to manifest
differently in those tissues. For example, let's say
hypothetically that your heart is infected with Borrelia
burgdorferi bacteria. Perhaps most people make an
antibody that suppresses attachment of Bb to certain
fibers in the heart. If you lack that antibody, the
infection may continue more aggressively and manifest
differently - for instance, causing an enlargement of
the muscle fibers or destruction of the conduction
pathways.
Instead of lacking a specific antibody, perhaps some
individuals make a different kind of antibody, an
antibody that not only attacks the bacteria - but may
attack the heart as well! It is well known and
documented that some patients produce auto-antibodies,
which are antibodies that our own body produces that
attack our own tissues. This is the basis of autoimmune
disease. In some Lyme disease patients, an auto-antibody
against cardiolipin has been clearly established in Lyme
patients with Lyme carditis.
Perhaps, in addition to other Lyme tests, we should
also be tissue typing patients and searching for
auto-antibodies? Tissue typing requires a small blood
sample, and costs about $200.
Western Blot
The Western Blot essentially makes a map of the
different antibodies the immune system produces to the
bacteria. The map separates the antibodies by the weight
of their respective antigens and are reported in units
called kilo daltons or kDa. For example, a Western Blot
may report bands at 22, 23, 25, 31, 34, 39, and 41 kDa.
Each of these bands represents an antibody response to a
specific protein found on the spirochete. The 41 band
indicates an antibody to the flagella 41 kDa protein and
is nonspecific. The 31 kDa band represents the OSPA
protein and is specific for just a few species of
Borrelia, as is the 34 band OSPB, and 23 kDa OSPC.
In 1994, the Association of State and Territorial
Public Health Laboratory Directors, under a CDC grant,
decided that there should be consistency between labs
reporting Lyme disease Western Blots, and that a
specific reporting criteria should be established. The
consensus committe, chaired by Dr. Michael Osterholm,
Ph.D., MN, set nationwide standards for Western Blot
reporting. This sounds good, but one could argue they
made a bad situation worse. Prior to the hearing,
virtually every lab had accepted bands 22, 23, 25, 31,
and 34 kDa as specific and significant, and reported
them as positive for exposure to Borrelia burgdorferi.
Not only are these bands specific for Borrelia species,
but they represent all of the major outer surface
proteins being used to develop the Lyme vaccines. The
committee, without any clear reasoning, disqualified
those bands as even being reportable.
After the consensus meeting, those bands were no
longer acceptable. The result was that what had been a
fair-to-good test for detecting Lyme disease had now
become poor, arguably useless. Many scientists have
questioned these new reporting criteria, and several
wrote letters of protest to both the committee and to
laboratory journals. Many labs stopped reporting the
actual bands and instead, simply reported the test as
positive or negative, thus preventing any further
interpretations. (90)
How badly did the Lab Directors bootstrap this test?
The following is an analysis of the new guidelines
presented as an abstract and lecture at the 1995
Rheumatology Conference in Texas, chaired by Dr. Alan
Steere, MD. (1995 Rheumatology Symposia Abstract #1254,
Dr. Paul Fawcett, et al.)
This was a study designed to test the recently
proposed changes to Western Blot interpretation by the
Second National Conference on Serological Testing for
Lyme Disease, sponsored by the CDC. The committee
proposed limiting the bands that could be reported in a
Western Blot for diagnosis of Lyme disease. Out of a
possible 25 bands, 10 specific bands were selected as
being reportable. An lgG Western Blot must have five or
more of these bands: 18, 21,28, 30, 39, 41,,45, 58, 66
and 93 kDa. An lgM Western Blot must have two or more of
the following three bands: 23, 39, 41.
Conspicuously absent are the most important bands,
22, 23, 25, 31, and 34, which include OSPA, OSP-B and
OSP-C antigens - the three most widely accepted and
recognized Bb antigens. These antigens were the antigens
chosen for human vaccine trials. This abstract showed
that, under the old criteria, all of 66 pediatric
patients with a history of a tick bite and bull's-eye
rash who were symptomatic were accepted as positive
under the old Western Blot interpretation.
Under the newly proposed criteria, only 20 were now
considered positive. (The number of false positives
under both criteria was zero percent.) That means 46
children who were all symptomatic would probably be
denied treatment! That's a success rate of only 31%.
*Note: A misconception about Western Blots is that
they have as many false positives as false negatives.
This is not true. False positives based on species
specific bands are rare.
The conclusion of the researchers was: "the proposed
Western Blot reporting criteria are grossly inadequate,
because it excluded 69% of the infected children."
Elisa Test
The Enzyme-Linked Immunosorbant Serum Assay is the
simplest, least expensive, easiest to perform, and most
common Lyme test ordered. It is a test based on
detecting the antibodies that our bodies make in
response to being exposed to Borrelia burgdorferi (Bb).
It is a preferred test by laboratories, not because it
is more accurate than other Lyme tests, but because it
is automated. Many different patient samples can be
performed by a single machine simultaneously. This
allows for a faster turnover, less costs, and
theoretically, standardized test results that are
consistent from lab to lab.
We are told by manufacturers, health departments and
clinics that the Lyme ELISA tests are good, useful
tests, but in two blinded studies that tested
laboratories for accuracy, they failed miserably. Lorie
Bakken, MS/MPH, showed in her studies that there was not
only inaccuracy and inconsistency between competing
laboratories, but also between identical triple samples
sent to the same lab. In other words, identical samples
often resulted in different results! In the first study,
forty-five labs correctly identified the samples only
55% of the time.
In the latest study by the College of American
Pathologists, 516 labs were tested. The overall result
was terrible! There were almost equal numbers of false
positives as false negatives. Overall, the labs were 55%
inaccurate. The labs could only give a correct result
45% of the time. You are actually better off to flip a
coin!
The basis of the ELISA test is that it can be primed
to be very specific for particular antibodies. This is
done by taking a laboratory sample of the Lyme bacteria
and breaking the sample down into fragments. These
fragments, or antigens, are then embedded on the side of
a reagent vessel like a test tube. Then the patient's
serum is added, and any free (non-complexed) antibodies
specific for the test strain will then bind to the
antigens, which are linked to special enzymes that will
change color when antibodies are present. The sample is
continually diluted until the reaction no longer occurs
and no color change can be detected. The sample is then
reported as a dilution ratio, such as one part serum to
256 parts water, or 1:256.
The ELISA test sounds simple and straight forward,
but it has a couple of major flaws. Borrelia species are
some of the most polymorphic bacteria known to exist. In
other words, most Borrelia species can significantly
change its surface proteins enough during cell division
as to evade our immune system, and may differ from
laboratory strains enough to result in negative tests,
even if antiBb antibodies are present! In Europe, this
problem is intensified because they have recognized
three species of Borrelia that cause Lyme disease, and
so they have available three separate ELISA tests. The
questions in America are: 1) Have we recognized all the
strains and species of Borrelia that cause Lyme disease
symptoms, and 2) are we incorporating them into our
tests? The answer is no. Convenience and expedience has
chosen that we don't prime our ELISA tests withwild
strains, but use a laboratory strain.
When a lab reports that their ELISA test has had high
specificity and high sensitivity, it is usually
interpreted by doctors as being a more accurate test,
but the doctors don't know what the lab is actually
measuring. One of the hidden problems of serologic Lyme
tests is the fact that the tests must be primed with a
source of bacteria to create the reactions with the
patient's antibodies. To do this, virtually all labs
rely on a laboratory strain of Bb known as strain
B-31.Taking purified antigens from strain B-31 and
injecting them into mice, they then can extract a
monoclonal antibody to each antigen, or a polyvalent
antibody soup. This antibody is concentrated and
purified, and then added to the ELISA test to test the
efficacy and performance of the test. Unlike the wild
strains, B-31 grows well in culture, and this makes it a
perfect choice as a consistent and inexpensive source of
Bb. But the affinity the mouse monoclonal antibody has
to B-31 antigen is quite different from the affinity the
patients' antibodies have to the same antigen. This
means the test may register as negative because the test
cannot detect the slightly different antibody profile
that a wild strain of Bb can produce. In other words,
the labs are really comparing apples to oranges! This is
why, when the American College of Pathologists used
human sera to test the accuracy of 516 different
laboratories ELISA tests nation wide, the overall
accuracy was only 45%.
In the quest for specificity, most ELISA tests have
become so specific that the test may fail to detect
antibodies from related strains of Borrelia. This would
include different genospecies that cause Lyme disease,
as well as different Borrelia species that cause
Tickborne Relapsing Fever. Would a cross reaction to the
Borrelia species that cause Tick-borne Relapsing Fever
be so bad?
The real Achilles' Heal of an ELISA Test is that it
can only detect free antibody. It cannot detect any
antibody that has become complexed with antigen.
The ELISA test depends on the active, free antibodies
to attach to the free antigens that have been embedded
on the walls of the test tube. If the antibodies in the
serum being tested are already attached to antigens,
then the enzyme reaction cannot take place. If we think
of antibodies as sort of keys that fit into locks, and
that on the surface of the bacteria are specific locks
we now call antigens, you can see that once a key is
inserted into a lock, the key is no longer available to
open any other locks.
What makes this test so misleading is that many
doctors accept high readings as an indication that the
patient must really be sick. This logic is exactly
backwards. If a patient is really infected with lots of
bacteria, that means they have a lot of bacterial
antigens floating around in the blood that are
complexing free antibodies. So, as free antigen
increases, free antibody decreases. Since the ELISA test
detects only free antibody, a negative test might
actually indicate a more serious infection. Many times,
I have seen totally asymptotic patients with ELISA
titers over 1000 be treated as though they were on
death's doorstep simply because they had a high titer,
while patients with borderline titers who are
practically disabled are ignored, because a low titer is
perceived as meaning less infected! These conclusions
are erroneous and actually opposite to the truth, which
is that a high titer means greater natural immunity.
This phenomena can actually be observed by using
vaccines. If a patient has been vaccinated for a disease
like tetanus, they will carry a high titer of free
antibodies. If you try to measure those antibodies an
hour after a booster shot is given, they will test
negative. This is because the injected tetanus antigen
complexes all available free antibody before the body
can make more, so the measurable free antibody level
drops.
The nature of all antibody is to seek out the proper
antigen. The level of free antibody available is
variable and often inadequate for the amount of antigen
available. As antigen increases (i.e. The bacteria are
dividing faster than the immune system can handle), free
antibody drops.
What a high ELISA test may be a better indicator of
is what level of immunity is the patient capable of
mounting against this infection? A high titer is the
same thing as saying the patient has a high natural
immunity, and a low can mean that the patient may be
overwhelmed by infection.
In one year-long study by Dr. Sam Donta, MD, done on
chronic Lyme patients, the initial ELISA tests proved to
be more than 66+% inaccurate (1996 LDF Conference
lecture). Other researchers have also found the ELISA
tests to be inaccurate. Using a 45-panel diagnostic
testing protocol from the NIH for testing the efficacy
of the ELISA and Western Blot, researchers found the
accuracy of the Lyme ELISA varied from about 5075%, and
were routinely inconsistent. The CDC's ELISA test did no
better on average than any other ELISA. It is the CDC
ELISA test which is used for surveillance of emerging
Lyme disease in the United States, yet the test was
correct only about two out every three tests. Too often,
a single negative ELISA test can prevent a sick patient
from getting treatment, even despite having serious
symptoms!
In my opinion, the ELISA test is worthless as a
diagnostic tool in Lyme disease. It is inconsistent and
inaccurate, and should be discontinued as a tool to
diagnose Lyme. If the NIH and CDC truly believe, as
they've stated, that the diagnosis of Lyme disease is to
be made on the basis of symptoms, then these tests
should be temporarily banned until each manufacturer can
prove efficacy using human serum. |