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The Test Sample
What is being tested?
Lyme disease is an infection caused by the bacteria Borrelia burgdorferi and Borrelia mayonii, which are carried primarily by the deer tick, also known as the black-legged tick. Lyme disease tests measure Borrelia antibodies in the blood, or in the cerebrospinal fluid (CSF) if there are signs and symptoms of central nervous system disease.
These antibodies are produced by the body's immune system in response to exposure to Borrelia, the bacteria that cause Lyme disease. Infected deer ticks or black-legged ticks transmit the bacteria to a person through a bite. The disease is most common in the spring and summer in the regions where these ticks live, such as the northeastern, mid-Atlantic, and midwestern United States.
Lyme disease infection causes symptoms that may include a characteristic erythema migrans (EM) or "bulls-eye" rash that spreads from the site of the bite, fever, chills, headache, and fatigue. If left untreated, Lyme disease may progress to cause intermittent joint pain and swelling, meningitis, facial paralysis (Bell's palsy), weakness and numbness in the arms and legs, memory problems, and may rarely affect the heart or eyes. For more on Lyme disease, read the condition article: Lyme Disease.
It takes the body's immune system some time to begin producing Borrelia antibodies. Lab tests can detect two different classes of antibodies. IgM antibodies are usually detectable about two to three weeks after onset of infection and IgG antibodies are detectable several weeks after onset of infection.
Two different types of tests are recommended by the Centers for Disease Control and Prevention (CDC) to detect these antibodies and confirm Lyme disease.
- The initial test may use an enzyme immunoassay (EIA) or immunofluorescence (IFA) method to measure Borrelia IgM and/or IgG antibodies.
- Since these tests may be positive with infections caused by other bacteria similar to Borrelia, such as the bacteria that cause syphilis, the CDC recommends that any positive or indeterminate test results then be followed by a second test, called a western blot, in order to confirm the findings.
For more, see the "How is it used?" section.
How is the sample collected for testing?
A blood sample is taken by needle from a vein in the arm. If there are signs and symptoms involving the central nervous system (meningitis), a sample of cerebrospinal fluid (CSF) is collected by a health practitioner from the lower back using a procedure called a lumbar puncture or spinal tap.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.