•  
  •  

Lyme Disease: Role of Blood Tests

Topic Overview

If you were exposed to ticks and you get an expanding, circular rash (erythema migrans), your doctor may treat you for Lyme disease without doing a blood test. Blood tests done in the first few weeks may not show Lyme disease even when you have the illness. This is because the body's immune system responds slowly to the bacteria that cause Lyme disease. Blood tests may not detect antibodies to the disease even though the infection may be present. So a negative test result at this stage does not rule out a diagnosis of Lyme disease.

Blood tests may be used if you have symptoms of later Lyme disease, such as problems involving the joints, heart, or nervous system. But current blood tests can't tell the difference between an active infection and a past infection that was treated and cured. Even at this later stage, a positive test does not always mean that you have active Lyme disease.

Related Information

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Christine Hahn, MD - Epidemiology
Last Revised August 31, 2010

Last Revised: August 31, 2010

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Christine Hahn, MD - Epidemiology

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

To learn more visit Healthwise.org

© 1995-2012 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.