3. Lyme Disease Test Kits: Potential for Misdiagnosis
(6,7) In summary, serologic testing is not useful early in the course of Lyme disease, because of the low sensitivity of tests in early disease. Several factors contribute to the limitations of using ELISA, IFA, or Western blot tests for...
http://www.fda.gov/medbull/summer99/Lyme.html

4. Lyme Disease and Related Tick-Borne Infections -- Hmh Home Page
Lyme disease is the most commonly reported and underreported, vector-borne disease in the United States. It should be noted that even if Lyme disease has been successfully treated, it may be possible to become reinfected with Lyme disease again...
http://www.hmh.net/adam/patientreports/000016.htm

5. Lyme disease and related tick-borne infections -- University Of Maryland Medical Center
They should never be used to make a primary diagnosis of Lyme disease in patients who do not have obvious symptoms of the disease. The patient may have been infected with Lyme disease previously and harbor antibodies to the disease.
http://www.umm.edu/patiented/articles/how_lyme_disease_diagnosed_000016_6.htm