Lyme disease
At a Glance
Why Get Tested?
To see if you have been exposed to the bacterium that causes Lyme disease
When to Get Tested?
If you show symptoms of Lyme disease and if you have recently been overseas to USA or Europe and may have had a tick bite. Lyme disease is not present in Australia.
Sample Required?
A blood sample drawn from a vein in the arm
Test Preparation Needed?
None
The Test Sample
What is being tested?
Your blood is being tested for antibodies to the Lyme disease bacterium. When you have these antibodies in your blood, it means that you may have come in contact with the Lyme disease spiral bacterium (spirochete) known as Borrelia burgdorferi, which is transmitted by a bite from an infected deer tick.
This test also measures antibodies to other spiral bacteria, so that if the test is positive, an additional test, called a Western Blot, is used to help your doctor confirm a diagnosis of Lyme disease.
How is the sample collected for testing?
A blood sample is taken by needle from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
The Test
How is it used?
The test is used to determine if your blood has made antibodies to the bacterium that causes Lyme disease. The infection affects many body systems, and in many patients starts with a ‘bulls-eye’ rash at the site of the bite and flu-like symptoms. The disease can progress and eventually cause a variety of chronic symptoms, including inflammation of the heart, arthritis, and central nervous system disease, including meningitis.
But because the symptoms of Lyme disease vary from person to person, and because antibodies to the bacterium do not appear until 6–8 weeks after the tick bite, the infection is difficult to diagnose. At this point, a blood test can be used to detect levels of antibodies, immunoglobulin M (IgM) and immunoglobulin G (IgG), that develop against the spiral Borrelia burgdorferi bacterium.
This test, however, can also detect antibodies to other spiral bacteria, such as those that cause syphilis and leptospirosis. Therefore, if the test is positive an additional test called a Western Blot, is often required to confirm the presence of specific antibodies to the bacterium that causes Lyme disease.
When is it requested?
If you have travelled overseas to an area with Lyme disease and you show the tell-tale sign of the tick bite. If you don’t have these clear signs but do have vague, confusing symptoms ranging from ‘flu’, numbness and muscle and joint ache to arthritis, fatigue and unexplained nerve or heart problems, your doctor may order these blood tests to see if you have Lyme disease.
What does the test result mean?
A healthy adult has no antibodies to the Borrelia burgdorferi bacterium. If you test positive, you may have been exposed to the bacterium and may have Lyme Disease. (It can take from 6 to 8 weeks after being bitten for antibodies to appear in the blood.) If you test negative, you could still have the disease, but your antibody level is too low to detect.
Is there anything else I should know?
Antibodies to this bacteria can stay in the blood for a long time; therefore if you have ever been infected with Borrelia burgdorferi previously, your blood test might still be positive even though you may no longer have Lyme disease.
Antibiotics can interfere with the test results, so if you are being treated with antibiotics before being tested for Lyme disease, make sure your doctor knows.
Common Questions
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Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
