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 the USA or Europe and may have had a tick bite. Lyme disease has never been proven to be present in Australia.

Sample required?

A blood sample drawn from a vein in the arm

Test preparation needed?

None

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 also known as the black-legged tick.

This test also measures antibodies to other spiral bacteria, so that if the test is positive, an additional test, called a Western Blot, more specific for Lyme disease, 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. Other more specialised tests such as DNA testing by PCR and culture of the organism from skin biopsies are under development (see the “testing advice for NSW clinicians” in the links at the end of this article). The NSW Department of Health recommends that testing should be performed in NATA-accredited laboratories (listed at www.nata.asn).

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.

The following table simplfies the test results. However, esults have to be interpreted by a doctor on a case by case basis.

IgM antibody Igg antibody Confirmatory test (western blot) Likely interpretation of lab tests
Positive Positive Positive Strongly suggest Lyme disease
Positive Negative Negative False-positive IgM test
Negative Positive Positive Late or previous infection
Negative Positive Negative False-positive IgG  test
Negative Negative Usually not performed when IgG and IgM are negative No infections present, symptoms may be due to another cause OR antibody levels are too low to detect

Is there anything else I should know?

Antibodies to these 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

What is the proper treatment for Lyme disease?

Most patients with Lyme disease are treated with antibiotics.

Can I do anything to protect myself from becoming infected?

Yes. If travelling overseas to USA or Europe and you are in the woods or garden in tick-infested areas, avoid contact with the soil, leaves, and vegetation. Wear closed shoes, light-coloured clothing and use insect repellant containing DEET. Check your clothing and exposed skin frequently and remove ticks promptly. Animals such as dogs, cats, horses and cows can also carry the deer tick.

How can I recognise the signs if I don’t show the rash?

The rash appears in only about 50% of those infected. This rash may be the classic ‘bull’s eye’ but may also be blotchy or red and may be confused with poison ivy, spider bites or ringworm. It may appear between a few days and a few weeks after being bitten and can disappear quickly. If possible, take a picture of the rash to show your doctor, since the rash may be gone before you can get an appointment.

Other symptoms of Lyme disease include fatigue, chills and fever, headache, muscle and joint pain and swollen lymph nodes. Check with your doctor if you have any of these symptoms and cannot explain how you got them.

Which countries are affected by Lyme disease?

Lyme disease is common in the US, particularly the forested areas of New England, and in Scandinavia. Other countries in Western and Eastern Europe, the former Soviet Union and Japan and China have all reported cases. Each year hundreds of thousands are infected in the US, while in the UK there are usually only a few hundred cases. Infections occur mainly in the northern hemisphere summer months ie. June and July. Lyme disease has not been found to occur in Australia. In the 1990s, 12,000 ticks were collected from different parts of NSW and were tested for Borrelia bacteria. No evidence of Borrelia infection could be found in any of the ticks collected.

It is possible that a disease which shares some symptoms with Lyme disease is present in Australia. If it exists it may or may not be transmitted by ticks. However until such a disease is characterised and the causative organism identified, it is not possible to develop a diagnostic test. Some non-NATA accredited laboratories in Australia and overseas offer tests that claim to show Lyme disease is relatively common in Australia. However Australian expert microbiologists and pathologists recommend that testing be performed only in NATA-accredited laboratories where the testing has been assessed by strict criteria to assure that false-positive and false-negative results are minimised.
 


Last Review Date: January 2, 2017