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Lyme Disease Test

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.
  • 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.

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

WebMD Medical Reference from Healthwise

Last Updated: August 21, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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