Lyme Disease Association
of Australia
Together we can fight Lyme Disease and win
How do you interpret Lyme Disease Blood Test
results?
Firstly, it must be stressed that Lyme Disease is NOT diagnosed on the basis of a
blood test. This is because there are currently too many false negative results. A
“negative” Lyme Disease blood test does not rule out a Lyme bacterial infection.
Lyme Disease is a clinical diagnosis based upon previous medical history and current
presenting symptoms – blood tests assist in guiding treatment, but should NOT be
used for diagnosis.
We need to note that currently the Lyme Disease Association of Australia (LDAA)
does not recommend being tested in Australia (except privately by PCR test although it is currently not as accurate as testing performed in the USA or Germany).
Anecdotally, we have found that the vast majority of testing for Lyme Disease is
unreliable. This is based on the fact that many of our members have tested negative
in Australia, but positive in the specialty Lyme Disease Blood Reference Laboratory
IGeneX in the United States at the same time. There are many different reasons for
this discrepancy, and we hope that testing in Australia will improve in the future.
However we currently can not recommend testing in Australia, as it is not reliable
enough at this stage.
Background : Why is it so hard to test for Lyme Disease? – firstly, the bacteria that
causes Lyme Disease often does not reside in the blood, but rather in tissues, organs,
the nervous system, and in collagen and joints, which makes it very difficult to isolate
during a PCR blood test.
Secondly, the vast majority of blood tests currently do not actually test for the Lyme
Disease bacteria itself, but rather the body’s immune response to it. Because of the
nature of Lyme Disease and its ability to depress the immune system, we have found
that the sicker the patient is, the less likely they are to return a positive result, as their
body has not been able to mount a strong immune defence against the Lyme Disease
bacteria.
www.lymedisease.org.au Thirdly, there are many different strains of Lyme Disease all around the world.
Currently there are 14 known genospecies of Borrelia Burgdorferi senso lato (the
bacteria that causes Lyme Disease), with more being discovered every year – the
Western Blot blood test, tests for 2 of these strains. Currently the strain of Borrelia
that causes Lyme Disease in Australia has not been isolated, and so it is not possible
to accurately test for the native Australian strain of Lyme Disease.
Fourthly, due to medical politics in the USA (which affects patients in Australia), it is
difficult to interpret Lyme Disease testing based on laboratory reporting. This is
because the Infectious Diseases Society of America (IDSA) has recommended that
Lyme Disease testing follow a two tier testing procedure, that firstly tests patients
using an ELISA test, and if this is positive, that it then be further confirmed via a
Western Blot blood test. The problem with this, is that the ELISA is insufficiently
sensitive to test for Lyme Disease [Trevejo R, JID 1999; 179:931–8.] and many
infected patients don’t get referred on for the Western Blot test. Also, the US Centre
for Disease Control (CDC) has stipulated that certain “bands” in the Western Blot test
must be positive in order for a Lyme test to be declared positive – the problem is that
these bands were chosen for statistical, rather than diagnostic criteria. For example,
the most specific bands for Lyme Disease (bands 31 and 34) were excluded from the
CDC criteria because they were used to create the Lyme Disease vaccine (which is
no longer available), thus eliminating valuable testing data. If you have not received
the Lyme Disease Vaccine and you test positive (“+”) or indeterminate (“IND”) to
bands 31 and 34, you probably have Lyme Disease. The CDC testing criteria actually
includes a number of bands which are not specific to Lyme Disease, which increases
the chances of a false negative, but only if the CDC criteria for test reporting is used.
What is the difference between “+”, “++”, “+++” and “IND”? These are the level to
which the laboratory technician can see the immune response to the specific part of
the bacteria. Both “++” and “+++” results are very rare, and show a strong immune
response to the Lyme Disease bacteria. If a patients immune response is
compromised (as it is in most Lyme Disease patients and particularly in patients with
neurological, late stage or severe Lyme Disease), a “IND” result is a weak positive
immune response to Lyme Disease and should be treated as a positive. result. After
treatment, many patients who are retested return stronger results, as their immune
system has been able to mount a more effective response against the Lyme Disease
bacteria.
What is the difference between the Western Blot IgG and IgM tests? – IgM is
generally regarded as the body’s response to recent exposure to Lyme Disease. IgG
is generally regarded as the body’s response over time (ie. longer term) to Lyme
Disease. Because the immune system is compromised in Lyme Disease, often the
IgG and IgM responses can become mixed up.
When should I test for Lyme Disease? It takes the body 6 weeks to 6 months to
make antibodies to Lyme Disease – therefore testing straight after a tick bite is not
recommended. Also, patients with late stage Lyme Disease will have an impaired
www.lymedisease.org.au immune response due to the interaction by the Lyme Disease bacteria in depressing
the immune system, making testing unreliable as well.
So, how do I interpret the Lyme Disease Blood test results??
Currently there are 9 identified bands specific to Lyme Disease 18, 23-25, 31, 34,
37, 39, 83 and 93. A “+” or “IND” to one of these bands is considered a
positive result. A “+” or “IND” to two or more of these bands is considered a
strong positive result.
Other bands on the Western Blot report such as 22, 28, 30, 41, 45, 58, 66, & 73,
all add significant weight to the result, but at this stage are not necessarily
considered as absolute specific for Lyme bacteria.
NOTE : It must be stressed that a Lyme Disease diagnosis is not based on a
blood test result, but is rather based on medical history and current presenting
symptoms – blood tests can assist in diagnosis, but should not be used to
base a diagnosis on. Also, almost all Lyme Disease patients have co-infections
such as Ehrlichia, Rickettsia, Babesia, Bartonella, Mycoplasma Fermentans,
Chlamydia Pneumonia, etc – these have their own testing and diagnostic
problems, but should be considered in the diagnosis and treatment of a patient
with Lyme Disease.
For more information regarding the bands
31 (also written as 31kDa) – is the outer surface protein A (ospA) – this is a classic
Lyme Disease band, used in the Lyme Disease vaccine
34 (also written as 34kDa) – this is the outer surface protein B (ospB) – this is also a
hallmark Lyme Disease antibody, but is excluded from CDC criteria.
23-25 (also written as 23-25 kDa) – these are the outer surface protein C. Patients
that have a 31 or 34, or 23-25 band have a 97% response rate to the correct antibiotic
treatment in conjunction with correct treatment for co-infections.
www.lymedisease.org.au www.lymedisease.org.au