Lyme Disease Tests
Lyme disease tests detect antibodies in your blood or cerebrospinal fluid to help diagnose infections caused by tick bites.
What are Lyme disease tests?
Lyme disease is a bacterial infection transmitted by the bite of an infected black-legged (deer) tick. The test looks for antibodies your immune system produces to fight the bacteria. An infected tick generally needs to be attached for 36 to 48 hours to transmit the disease.
What are they used for?
Tests are used to confirm a diagnosis in patients who have symptoms and a history of potential tick exposure. In the U.S., infected ticks are most common in the Northeast, Mid-Atlantic, Upper Midwest, and Pacific coast.
Why do I need a Lyme disease test?
You may need testing if you show signs of infection 3 to 30 days after a potential tick bite.
Early Symptoms
- A reddish, round skin rash (sometimes a "bull's-eye" pattern)
- Fever, chills, and headache
- Fatigue and muscle/joint aches
- Swollen lymph nodes
Later Symptoms
- Severe headaches and neck stiffness
- Facial palsy (drooping of the face)
- Arthritis with severe joint pain and swelling
- Heart rhythm irregularities (arrhythmia)
- Shooting pains, numbness, or tingling in hands or feet
What happens during Lyme disease testing?
Testing is usually performed on a blood sample. If the infection is suspected to have spread to the nervous system, a lumbar puncture (spinal tap) may be performed to collect cerebrospinal fluid (CSF). During a spinal tap, a provider inserts a needle between the vertebrae in your lower spine to withdraw a small amount of fluid.
Will I need to do anything to prepare for the test?
No preparation is needed for a blood test. For a lumbar puncture, you may be asked to empty your bladder and bowels beforehand.
Are there any risks to Lyme disease tests?
Blood tests carry minimal risk. A lumbar puncture may cause temporary back pain, tenderness, or a headache that can last from several hours to a week.
What do the results mean?
Diagnosis is complex because symptoms overlap with other conditions.
- Negative: No antibodies were found. If symptoms have lasted less than 30 days, you may need a follow-up test, as it takes time for the body to produce detectable antibodies.
- Positive: Antibodies were found. The CDC recommends a second, confirmatory blood test. A positive result does not always mean current infection, as antibodies can persist from past, successfully treated cases.
- False Positives: The test may occasionally react to antibodies from other diseases, such as autoimmune conditions.
Is there anything else I need to know?
Be cautious with at-home test kits. Some use unproven methods, and results may not be accurate. Always consult your health care provider before pursuing at-home testing.