Use two-tier serological testing for diagnosis

Lyme disease diagnosis uses a two-step blood test: an initial ELISA (enzyme immunoassay) followed by a confirmatory Western blot or a second EIA. The newer modified two-tier testing (MTTT) replaces the Western blot with a second EIA, improving sensitivity for early infection while maintaining specificity.

Why It Works

A single test has too many false positives or negatives. The two-tier approach filters out cross-reactive antibodies from other conditions. The MTTT algorithm, FDA-approved since 2019, improves detection of early Lyme by 15-30% compared to the standard approach, especially important since single-tier sensitivity in early localized infection is only about 50%.

Tips

• Antibodies take 2-4 weeks to develop; testing too early produces false negatives
• A negative test does not rule out Lyme in the first few weeks after a tick bite
• If clinical suspicion is high (erythema migrans rash), treat empirically without waiting for results
• Standard US test panels may miss European Borrelia species (B. garinii, B. afzelii)