Lyme Disease, Molecular Detection, PCR
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Lyme disease is a multisystem and multistage tick-transmitted infection caused by spirochetal bacteria in the Borrelia burgdorferi sensu lato (Bbsl) complex.(1) Nearly all human infections are caused by 3 Bbsl species; Borrelia burgdorferi sensu stricto (hereafter referred to as Borrelia burgdorferi) is the primary cause of Lyme disease in North America, while Borrelia afzelii and Borrelia garinii are the primary causes of Lyme disease in Europe. Recently, Candidatus Borrelia mayonii has been identified as a second cause of Lyme disease in the United States.(2) Only 6 cases of Borrelia mayonii infection have been described to date, and all patients reported exposure to ticks in Minnesota or Wisconsin.
Lyme disease is the most commonly reported tick-borne infection in Europe and North America, causing an estimated 300,000 cases in the United States each year, and 85,000 cases in Europe.(3,4) The clinical features of Lyme disease are broad and may be confused with various immune and inflammatory disorders. The classic presenting sign of early localized Lyme disease caused by Borrelia burgdorferi is erythema migrans (EM), which occurs in approximately 80% of individuals. Other early signs and symptoms include malaise, headache, fever, lymphadenopathy, myalgia and arthralgia. Arthritis, neurological disease, and cardiac disease may be later stage manifestations. The chronic skin condition, acrodermatitis chronicum atrophicans, is also associated with Borrelia afzelii infection.
The presence of EM in the appropriate clinical setting is considered diagnostic for Lyme disease and no confirmatory laboratory testing is needed. In the absence of a characteristic EM lesion, serologic testing is the diagnostic method of choice for Lyme disease.(5) However, serology may not be positive until 2 to 4 weeks after onset of symptoms, and may show decreased sensitivity for detection of infection with Borrelia mayonii. Therefore, detection of Bbsl DNA using PCR may be a useful adjunct to serologic testing for detection of acute disease. PCR has shown utility for detection of Borrelia DNA from skin biopsies of EM lesions, as well as DNA from synovial and cerebrospinal fluid in late-stage disease.(6) Lyme PCR should always be performed in conjunction with FDA-approved serologic tests, and the results should be correlated with serologic and epidemiologic data and clinical presentation of the patient. The Mayo Clinic Lyme PCR test detects and differentiates the causes of Lyme disease in North America (Borrelia burgdorferi and Borrelia mayonii) and Europe (Borrelia afzelii and Borrelia garinii).
Confirmation of active Lyme disease
Supporting the diagnosis of Lyme arthritis
Testing of cerebrospinal fluid (CSF) by PCR in patients with suspected Lyme neuroborreliosis should be requested only on patients with positive Borrelia burgdorferi antibody in serum confirmed by Western blot assay LYWB / Lyme Disease Antibody, Immunoblot, Serum and with abnormal CSF findings (elevated protein and WBC >10 cells/high-power field).
A positive result indicates the presence of DNA from Borrelia burgdorferi, Borrelia mayonii, Borrelia afzelii, or Borrelia garinii, the agents of Lyme disease.
A negative result indicates the absence of detectable target DNA in the specimen. Due to the clinical sensitivity limitations of the PCR assay, a negative result does not preclude the presence of the organism or active Lyme disease.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Serologic tests are recommended for diagnosis of Lyme disease. PCR may play an adjunctive role, but may not detect Borrelia burgdorferi DNA from cerebrospinal fluid (CSF) in cases of active or chronic disease. The presence of inhibitory substances may also cause a false-negative result. If clinical features of illness are highly indicative of Lyme neuroborreliosis, serologic testing on CSF is warranted. PCR test results should be used as an aid in diagnosis and not considered diagnostic by themselves. These results should be correlated with serologic and epidemiologic data and clinical presentation of the patient.
Concurrent infections with multiple tick-borne pathogens, including Ehrlichia muris eauclairensis, Anaplasma phagocytophilum, Babesia microti, and Borrelia miyamotoi (a relapsing fever Borrelia) have been reported in United States, and consideration should be given to testing for other pathogens if clinically indicated.
This assay detects some members of the Borrelia burgdorferi sensu lato (Bbsl) complex that are not considered to be human pathogens, but may be found in ticks and other animals. Therefore, this assay should not be used to test nonhuman specimens.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
2. Pritt BS, Mead PS, Johnson, DKH, et al: Identification of a Novel Pathogenic Borrelia Species Causing Lyme Borreliosis with Unusually High Levels of Spirochetemia: A Descriptive Study. Lancet Infectious Diseases 2016;In Press
3. Hinckley AF, Connally NP, Meek JI, et al: Lyme disease testing by large commercial laboratories in the United States. Clin Infect Dis 2014;59(5):676-681
4. Lindgren E, Jaenson TGT: Lyme borreliosis in Europe: influences of climate and climate change, epidemiology, ecology and adaptation measures. Copenhagen, Denmark: World Health Organization; 2006
5. Centers for Disease Control and Prevention. Recommendations for test performance and interpretation from the Second National Conference on Serologic Diagnosis of Lyme Disease. MMWR Morb Mortal Wkly Rep 1995;44(31):590-591
6. Babady NE, Sloan LM, Vetter EA, et al: Percent positive rate of Lyme real-time polymerase chain reaction in blood, cerebrospinal fluid, synovial fluid, and tissue. Diagn Microbiol Infect Dis 2008;62(4):464-466
7. CDC: Recommendation for test performance and interpretation. From second national conference on serological diagnosis of lyme disease. MMWR Morb Mortal Wkly Rep 1996;45:481-484