Which sequence is standard for Lyme disease testing?

• A. ELISA first, then Western blot
• B. Western blot first, then ELISA
• C. PCR first
• D. Culture first

Answer: (A)

The main idea is that Lyme disease testing uses a two-step approach to balance sensitivity and specificity. Start with a highly sensitive screening test, such as an ELISA, to detect antibodies against Borrelia burgdorferi. If the ELISA is positive or equivocal, follow with a Western blot to confirm the result because it has higher specificity and requires antibodies to multiple Borrelia antigens. This combination reduces false positives that could come from the initial screen. PCR and culture aren’t used as the standard first-line sequence in typical testing because they have limited sensitivity or practicality in routine serology, so they don’t serve as the two-step framework.