Discusses antibody test used to detect Lyme disease. Covers two types of test (enzyme-linked immunosorbent assay and Western blot test). Covers why and how they are done. Includes info on what results mean.
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 two 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.
Western blot test. This test also identifies Lyme
disease antibodies and can confirm the results of an ELISA test. It is
most often done to detect a chronic Lyme disease infection.
Antibody testing should be done in a two-step
process, using the ELISA followed by the Western blot test. The Western blot test (which is a more specific
test than the ELISA) should be done in all people who have tested positive or borderline
positive (equivocal) in an ELISA 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.
Why It Is Done
A Lyme disease test is done to diagnose
Lyme disease in people who have symptoms of Lyme disease. Symptoms may
An expanding red rash with a pale center. This
is sometimes called a "bull's-eye" rash.
Headache and stiff neck.
and joint pain.
Symptoms of chronic Lyme disease infection include joint
pain, stiffness, and problems with the heart, brain, or nerves.
Testing is most accurate when you have
risk factors for Lyme disease or symptoms of the
How To Prepare
You do not need to do anything before
you have this test.
Talk to your doctor about any concerns you
have regarding the need for the test, its risks, how it will be done, or what
the results will mean. To help you understand the importance of this test, fill
medical test information form(What is a PDF document?).
How It Is Done
The health professional taking a sample
of your blood will:
Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
Clean the needle site with
Put the needle into the vein. More than one needle stick
may be needed.
Attach a tube to the needle to fill it with
Remove the band from your arm when enough blood is
Put a gauze pad or cotton ball over the needle site as
the needle is removed.
Put pressure on the site and then put on a
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
There is very little chance of a problem from
having a blood sample taken from a vein.
You may get a small bruise at the site. You
can lower the chance of bruising by keeping pressure on the site for several
In rare cases, the vein may become swollen after the
blood sample is taken. This problem is called phlebitis. A warm compress can be
used several times a day to treat this.
Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
Test results are
usually available in 1 to 2 weeks.
Lyme disease test
No antibodies to Lyme disease bacteria are
The polymerase chain reaction (PCR) test
does not find any Lyme disease bacteria
Antibodies to Lyme disease bacteria are
The polymerase chain reaction (PCR) test
detects Lyme disease bacteria DNA.
Normal (negative) values
A normal, or negative,
test for Lyme disease can mean one of the following:
You do not have Lyme disease. A negative PCR
test usually means that you do not have a Lyme disease infection.
You have Lyme disease but it does not show up on the test (false-negative). This is more likely with the antibody
tests than with PCR. Reasons for a false-negative result include the following:
You have not yet made antibodies to the
Lyme disease bacteria. The infection may be present, but it is too early to
find antibodies. This is most likely to occur during the first several weeks of
Blood levels of antibodies against Lyme disease bacteria
are too low for the test to detect.
Occasionally, some people who
were not treated correctly with antibiotics in the early stage of infection may
not have antibodies to the Lyme disease bacteria in later stages of the
Abnormal (positive) values
An abnormal, or
positive, test for Lyme disease can mean one of the following:
If antibodies are found, you may either have
Lyme disease now or had the illness in the past. Once you have a Lyme disease
infection, antibodies to the bacteria will usually stay in your body for the
rest of your life.
If Lyme disease bacteria DNA is found, you probably have an
active Lyme disease infection.
It may be hard to tell if you have Lyme
disease. False-positive and false-negative Lyme disease test results are
common. Many people do not make antibodies to Lyme disease bacteria for up to 8
weeks after being infected.
When an ELISA test is positive, a
Western blot test is usually done to confirm the diagnosis of Lyme
Doctors often do not rely on test results alone when
recommending treatment for a person who may have Lyme disease. Treatment is
often based on a person's
symptoms, the time of year, having a tick bite, and
risk factors for Lyme disease.
antibodies to the bacteria that cause Lyme disease does not always mean that an
active Lyme disease infection is causing your symptoms. It only means that you
were infected at one time.
Other Works Consulted
American Academy of Pediatrics (2009). Lyme disease. In LK Pickering, ed., Red Book: 2009 Report of the Committee on Infectious Diseases, 28th ed., pp. 430–435. Elk Grove, IL: American Academy of Pediatrics.
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
National Institutes of Health, U.S. Department of Health and Human Services (2008). Lyme Disease: The Facts, the Challenge (NIH Publication No. 08-7041). Available online: http://www.niaid.nih.gov/topics/lymeDisease/Documents/lymedisease.pdf.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
How this information was developed to help you make better health decisions.