Is a third Lyme test necessary after two negative tests 5 weeks apart following tick removal?

No Third Lyme Test Needed After Two Negative Tests 5 Weeks Apart

A third Lyme test is not necessary after two negative tests performed 5 weeks apart following a tick removal. 1

Rationale for Not Requiring a Third Test

The 2021 IDSA/AAN/ACR guidelines provide clear direction on this issue:

1. Testing Asymptomatic Individuals: The guidelines strongly recommend against testing asymptomatic patients for exposure to B. burgdorferi following an Ixodes tick bite 1

2. Serologic Response Timeline: When testing is indicated, convalescent-phase serum samples should be collected at least 2-3 weeks after the acute-phase sample 1

3. Two-Tier Testing Approach: The standard approach involves initial screening followed by confirmatory testing if the first test is positive

When Lyme Testing is Actually Indicated

Testing for Lyme disease is only recommended in specific clinical scenarios:

• Patients with acute disorders such as:

  • Meningitis
  • Painful radiculoneuritis
  • Mononeuropathy multiplex
  • Acute cranial neuropathies (particularly VII, VIII)
  • Spinal cord inflammation
  • AND with epidemiologically plausible exposure to infected ticks 1

• Patients with acute myocarditis/pericarditis of unknown cause in an appropriate epidemiologic setting 1

Common Pitfalls to Avoid

1. Overtesting: Testing without appropriate clinical indications leads to false positives and unnecessary treatment

2. Misinterpreting Test Results: Two negative tests 5 weeks apart provide strong evidence against Lyme infection

3. Testing in Low-Probability Scenarios: The positive predictive value of testing is poor in patients without appropriate symptoms or epidemiologic risk

What to Watch For Instead

Rather than pursuing additional testing, monitor for development of symptoms that would indicate Lyme disease:

• Erythema migrans (the characteristic rash)
• Flu-like symptoms (fever, fatigue, headache, muscle aches)
• Joint pain, particularly in large joints
• Neurological symptoms (facial palsy, meningitis symptoms)
• Cardiac symptoms (palpitations, chest pain, lightheadedness) 1, 2

If any of these symptoms develop, clinical reassessment would be warranted, but in the absence of symptoms after two negative tests 5 weeks apart, further testing is not indicated.