Lyme Disease Test
A Lyme disease test detects
antibodies to the
Lyme disease bacteria Borrelia burgdorferi in the blood. Lyme disease bacteria are spread by certain
kinds of ticks.
Lyme disease can be hard to diagnose because its
symptoms are similar to those of many other illnesses. If you and your doctor
think you have Lyme disease, your doctor will do a careful medical history and
physical exam. Antibody tests can sometimes be used to help identify Lyme
disease. Other tests may be done in certain situations.
Antibody tests are the most
commonly used tests to help identify Lyme disease. Antibody testing may also be
done on fluid from the spine or from a joint.
It may take up to 2
months after becoming infected before antibodies can be detected in a blood
test. Once formed, antibodies usually stay in your system for many years, even
after successful treatment of the disease. Finding antibodies to the Lyme
disease bacteria does not tell whether you were infected recently or sometime
in the past.
There are three types of antibody tests to detect
- Enzyme-linked immunosorbent assay (ELISA). This
common and rapid test to identify Lyme disease antibodies is the most sensitive
screening test for Lyme disease.
- Indirect fluorescent antibody (IFA). This test
also screens for Lyme disease antibodies.
- Western blot test. This test also identifies Lyme
disease antibodies and can confirm the results of an ELISA or IFA test. It is
most often done to detect a chronic Lyme disease infection.
Antibody testing should be done in a two-step
process, using either the ELISA or IFA followed by the Western blot test. ELISA
is considered a more reliable and accurate test than IFA, but IFA may be used
if ELISA is not available. The Western blot test (which is a more specific
test) should be done in all people who have tested positive or borderline
positive (equivocal) in an ELISA or IFA test.
- Polymerase chain reaction (PCR) test. Polymerase
chain reaction (PCR) testing detects the genetic material (DNA) of the Lyme disease bacteria. PCR testing may be
used to identify a current (active) infection if you have symptoms of Lyme
disease that have not gotten better with antibiotic treatment. PCR testing is
not done as often as antibody testing because it requires technical skill and
expensive equipment. Also, standards have not yet been developed for PCR
testing and there is a risk of
false-positive test results.
- Skin culture. A skin culture checks a tissue
sample for the bacteria that causes Lyme disease. It may take several weeks for
test results to come back. For this reason, antibody testing is done more often
than a tissue culture.