Do I need to retest for Lyme disease if I've had a previous Lyme scan?

Retesting for Lyme Disease After Previous Testing

Retesting for Lyme disease is generally not recommended unless there are new symptoms or evidence of reinfection, as antibodies can persist for years after initial infection. 1

When Retesting is Appropriate

Retesting for Lyme disease should be considered in the following specific scenarios:

1. Suspected Reinfection

• In cases of suspected reinfection, a detailed history and thorough physical examination are essential 1
• Most patients with reinfection will present with erythema migrans (EM) rash
• For patients without EM but with suspected reinfection, serologic testing is recommended but results should be interpreted cautiously

2. Monitoring Response to Treatment

• For patients with neurologic manifestations or other severe forms of Lyme disease, follow-up testing may be considered to monitor response to treatment 1
• However, routine follow-up testing is not recommended for uncomplicated cases that have responded to treatment

3. New or Persistent Symptoms

• New onset of symptoms that are consistent with Lyme disease manifestations, particularly if there has been new tick exposure in endemic areas
• For persistent symptoms after treatment (Post-Treatment Lyme Disease Syndrome), additional testing is generally not helpful as antibodies may persist for years 2

Interpreting Retesting Results

When retesting is performed, results should be interpreted with the following considerations:

• Antibody Persistence: Antibodies to B. burgdorferi can persist for years after successful treatment, making interpretation of positive results difficult 1
• Acute and Convalescent Testing: In cases of suspected reinfection, it may be helpful to conduct acute-phase and convalescent-phase serologic analysis to detect an increase in antibody titer or an increase in the number of antibody bands 1
• False Positives: In low-prevalence areas or in patients with low pretest probability, false positive results are more likely than true positives 1

Common Pitfalls to Avoid

1. Unnecessary Retesting: Routine retesting after successful treatment provides little clinical value and may lead to confusion due to antibody persistence 1, 2

2. Overreliance on Serology: Attributing non-specific symptoms to Lyme disease based solely on positive serology without clinical correlation 2

3. Extended Antibiotic Courses: Treating persistent symptoms with prolonged courses of antibiotics is not supported by evidence and is explicitly discouraged 2

4. Misinterpreting Test Results: Positive serologic results in patients from non-endemic areas without travel history to endemic regions have poor predictive value 1

5. Unvalidated Testing Methods: Using unvalidated test methods such as urine antigen tests or blood microscopy for detection of Borrelia species 1

Special Considerations

• For patients with psychiatric illness, routine testing for Lyme disease is not recommended 1
• In patients with developmental, behavioral, or psychiatric disorders, testing for Lyme disease is not routinely recommended 1
• In patients with typical amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, dementia, or new-onset seizures, routine testing for Lyme disease is not recommended 1

By following these evidence-based guidelines, unnecessary testing can be avoided while ensuring appropriate diagnosis and management of potential reinfection or new Lyme disease cases.