Lyme Disease Tests
Reviewed
Also called: Lyme antibodies detection, Borrelia burgdorferi antibodies test, Borrelia DNA Detection, IgM/IgG by Western Blot, Lyme disease test (CSF), Borrelia antibodies, IgM/IgG
Lyme disease tests detect antibodies your immune system makes against the bacteria that cause Lyme disease. They are used to help diagnose infection after a tick bite, especially if you have symptoms. Tests are done on blood or, if nervous system involvement is suspected, on cerebrospinal fluid. Results are interpreted together with your symptoms and exposure history.
Specimen: Blood or cerebrospinal fluid (CSF)
Why this test may be ordered
- To help diagnose Lyme disease infection if you have symptoms and possible tick exposure.
- To evaluate whether Lyme disease has spread to your nervous system (CSF test).
Preparation and collection
No special preparation for a blood test. For a lumbar puncture, you may be asked to empty your bladder and bowels beforehand.
Blood sample from a vein in your arm, or cerebrospinal fluid (CSF) via lumbar puncture.
Blood test: slight pain or bruising at the needle site, usually mild and brief. Lumbar puncture (CSF test): pinch or pressure when the needle is inserted; possible back pain, bleeding at the site, or headache that may last hours to a week or more.
Understanding results
Lyme disease test results are interpreted along with your medical history, exposure, and symptoms. A single test cannot confirm or rule out the disease. Your healthcare provider will consider the following patterns.
- Negative blood test: No antibodies to Lyme disease bacteria were found in your blood. If you have had symptoms for more than 30 days, Lyme disease is unlikely. Limitation: If you have had symptoms for less than 30 days, you may still be infected even if the test is negative (false negative). Next step: Your healthcare provider may recommend a repeat test after a few weeks if symptoms persist.
- Positive blood test (initial): Antibodies to Lyme disease bacteria were found in your blood. This may indicate a current or past infection. Limitation: Positive results do not always mean current Lyme disease; they could be from a past infection or a false positive from other antibodies. Next step: The CDC recommends a second blood test on the same sample. If the second test is positive and you have symptoms, you likely have Lyme disease. Your healthcare provider will prescribe antibiotics.
- Negative CSF test: No Lyme antibodies were found in your cerebrospinal fluid. Limitation: A negative CSF test does not rule out Lyme disease in the nervous system. Next step: Your healthcare provider may order additional tests or consider other diagnoses.
- Positive CSF test: Lyme disease antibodies were found in your cerebrospinal fluid, suggesting possible spread to the nervous system. Limitation: A positive CSF test may indicate nervous system involvement, but other conditions can cause similar findings. Next step: Your healthcare provider will assess the ratio of CSF antibodies to blood antibodies. If more antibodies are in the CSF, nervous system involvement is more likely. Antibiotic treatment will be prescribed.
- Test results alone cannot diagnose Lyme disease; your healthcare provider must consider your medical history, exposure, symptoms, and possibly other tests.
- Blood tests may be negative early in infection (false negative) because it takes weeks for antibodies to appear.
- Positive blood tests may be false positive (e.g., from other bacterial infections or autoimmune diseases) or from a past resolved infection.
- CSF test negative does not rule out nervous system involvement; more tests may be needed.
What to do next
Your healthcare provider will interpret your test results along with your symptoms, exposure history, and physical exam. If Lyme disease is likely, you will be prescribed antibiotics.
- What were my potential tick exposures?
- When did my symptoms start?
- Do I have any other conditions that could affect test results?