Test Overview
A Lyme disease test detects
antibodies to the
Lyme disease bacteria Borrelia
burgdorferi in the blood. Lyme disease bacteria is spread by certain kinds of ticks.
Lyme disease may be hard to
detect 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
Antibody tests are the most commonly used tests to help
identify Lyme disease and keep track
of its treatment. 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 Lyme disease.
- 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.
Other tests
- 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.