Test Overview

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

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
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.
  • 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.

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.

Why It Is Done

A Lyme disease test is done to diagnose
Lyme disease in people who have symptoms of Lyme disease. Symptoms may
include:

  • An expanding red rash with a pale center. This
    is sometimes called a “bull’s-eye” rash.
  • Extreme tiredness.
  • Fever.
  • Headache and stiff neck.
  • Muscle
    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
disease.

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
out the
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
    alcohol.
  • Put the needle into the vein. More than one needle stick
    may be needed.
  • Attach a tube to the needle to fill it with
    blood.
  • Remove the band from your arm when enough blood is
    collected.
  • 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
    bandage.

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
pinch.

Risks

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
    minutes.
  • 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.

Results

A Lyme disease test detects
antibodies to the
Lyme disease bacteria Borrelia burgdorferi in the blood.

Test results are
usually available in 1 to 2 weeks.

Lyme disease test
Normal (negative):

No antibodies to Lyme disease bacteria are
found.

The polymerase chain reaction (PCR) test
does not find any Lyme disease bacteria
DNA.

Abnormal (positive):

Antibodies to Lyme disease bacteria are
found.

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
      infection.
    • 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
      illness.

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.
  • The result is a
    false-positive. Sometimes an antibody test for Lyme
    disease finds antibodies to other bacteria, such as
    syphilis, or viruses, such as the
    Epstein-Barr virus or the
    human immunodeficiency virus (HIV). The test may also
    find antibodies that develop as part of an immune response against the body’s
    own tissues (autoimmune disease), such as
    rheumatoid arthritis or
    lupus. Your doctor may not be able to tell if the
    antibodies found in these tests are caused by a current Lyme disease
    infection.

The PCR test may be done to confirm an infection if you
have a positive antibody test result.

What Affects the Test

Reasons you may not be able to
have the test or why the results may not be helpful include:

  • You have a viral infection, such as Epstein-Barr virus or
    HIV.
  • You have another bacterial infection, such as
    syphilis.
  • You have high
    lipid levels.

What To Think About

  • 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.
  • 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
    other
    risk factors for Lyme disease.

References

Other Works Consulted

  • Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
  • 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.

Credits

ByHealthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD – Internal Medicine
Adam Husney, MD – Family Medicine
Specialist Medical Reviewer Christine Hahn, MD – Epidemiology
W. David Colby IV, MSc, MD, FRCPC – Infectious Disease

Current as ofMarch 3, 2017