The ELISA test for Lyme disease can yield false positives in which condition?

The ELISA test for Lyme disease can yield false positives in which condition?

• A. False
• B. Syphilis
• C. Malaria
• D. Influenza

Answer: (B)

Lyme disease serology relies on antibodies to Borrelia burgdorferi, but the ELISA can pick up antibodies that react with similar antigens from other infections. Syphilis, caused by Treponema pallidum, is a classic source of such cross-reactive antibodies because both are spirochetes sharing similar antigenic components. That shared reactivity can make the Lyme ELISA positive even when Borrelia isn’t present. To reduce this, clinicians use a two-tier approach, confirming with a second test like Western blot when the initial screen is positive. Other conditions like malaria or influenza don’t involve those same cross-reactive spirochetal antibodies, so they are not as likely to cause a false-positive Lyme ELISA.

Lyme disease serology relies on antibodies to Borrelia burgdorferi, but the ELISA can pick up antibodies that react with similar antigens from other infections. Syphilis, caused by Treponema pallidum, is a classic source of such cross-reactive antibodies because both are spirochetes sharing similar antigenic components. That shared reactivity can make the Lyme ELISA positive even when Borrelia isn’t present. To reduce this, clinicians use a two-tier approach, confirming with a second test like Western blot when the initial screen is positive. Other conditions like malaria or influenza don’t involve those same cross-reactive spirochetal antibodies, so they are not as likely to cause a false-positive Lyme ELISA.