Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

2. Incorrect

Some people have heard that the blood test for Lyme disease is "positive in less than 65% of cases" and believe that this applies to ALL patients and ALL stages of disease. This is not true.

The "two-tiered" blood test measures antibodies that the human body naturally makes to "fight off" infection. The blood is analyzed first with a test known as ELISA or EIA. If the result is positive or borderline, then a second test, known as a Western Blot, should be performed.

It will typically take up to several weeks after a person is infected for the test to produce a positive result. This delay is common for antibody tests. In particular, patients with a pink or reddish "bulls-eye" rash (erythema migrans) may have negative test results early in the illness. However, patients who have been ill and infected for more than a few weeks will test positive 85-100% of the time.

If you have been ill for months or years and test negative for Lyme disease using the current two-tier testing, it is unlikely that Lyme disease is the cause of your symptoms.

Go to next question

 
Contact Us:
  • Centers for Disease Control and Prevention
    Bacterial Diseases Branch
    Foothills Campus
    Fort Collins, CO 80521
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
  • Contact CDC–INFO
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #