Is it within my scope as a psychiatric nurse practitioner (PNP) to order a blood test for Lyme disease, and if so, what is the recommended test?

Ordering Lyme Disease Testing as a Psychiatric Nurse Practitioner

It is not recommended for psychiatric nurse practitioners to routinely order Lyme disease testing for patients with psychiatric illness, as the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR) guidelines strongly recommend against routine testing for Lyme disease in patients with psychiatric illness. 1

Recommendations Against Routine Testing in Psychiatric Patients

• The 2021 IDSA/AAN/ACR clinical practice guidelines explicitly state: "In patients with psychiatric illness, we recommend against routine testing for Lyme disease" (strong recommendation, low-quality evidence) 1

• Similarly, for children presenting with developmental, behavioral, or psychiatric disorders, the guidelines suggest against routinely testing for Lyme disease (weak recommendation, low-quality evidence) 1

When Testing Might Be Appropriate

Testing for Lyme disease may be considered in specific circumstances:

• When patients present with neurological symptoms that could be consistent with Lyme neuroborreliosis AND have epidemiologically plausible exposure to ticks infected with B. burgdorferi 1

• Specifically, testing is recommended for patients with one or more of the following acute disorders with appropriate exposure history:

  • Meningitis
  • Painful radiculoneuritis
  • Mononeuropathy multiplex
  • Acute cranial neuropathies (particularly VII, VIII, less commonly III, V, VI)
  • Evidence of spinal cord inflammation with painful radiculitis 1

Recommended Testing Method

If testing is clinically indicated based on the above criteria, the recommended approach is:

• A two-tiered serologic testing algorithm consisting of:

  • Initial enzyme-linked immunoassay (EIA) or immunofluorescence assay (IFA)
  • If positive or equivocal, followed by a reflex Western immunoblot test 2, 3

• For samples drawn within four weeks of disease onset, both IgM and IgG antibodies should be tested; for samples drawn more than four weeks after onset, only IgG should be tested 4

• Serum antibody testing is recommended rather than PCR or culture of cerebrospinal fluid or serum for suspected Lyme neuroborreliosis 1

Important Caveats and Pitfalls

• False-positive Lyme titers can occur in patients with certain conditions (e.g., infectious mononucleosis, autoimmune diseases) 2

• The standard two-tiered testing approach has high specificity (>98%) but lower sensitivity in early disease 2

• Serologic testing in patients with nonspecific symptoms and low probability of Lyme disease carries a high risk of false-positive results 4, 5

• There is no biologic or clinical trial evidence indicating that prolonged antibiotic therapy is beneficial for patients with persistent symptoms following standard treatment 3

Conclusion

While psychiatric nurse practitioners may have the technical ability to order laboratory tests, the clinical practice guidelines strongly recommend against routine Lyme disease testing in patients with psychiatric illness unless there are specific neurological symptoms and appropriate exposure history. When testing is indicated, it should follow the two-tiered approach with appropriate interpretation of results.