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; B burgdorferi sensu stricto (hereafter referred to as B burgdorferi) is the primary cause of Lyme disease in North America, while B afzelii and B garinii are the primary causes of Lyme disease in Europe. In 2012, B mayonii has been identified as a less common cause of Lyme disease in the upper Midwestern United States.(2,3) This organism has only been detected in patients with exposure to ticks in Minnesota and Wisconsin and has not been detected in over 10,000 specimens from patients in other states including regions of northeast where Lyme disease is endemic.
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.(4,5) 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 B burgdorferi is erythema migrans (EM), which occurs in approximately 80% of individuals. Other early signs and symptoms include malaise, headache, fever, lymphadenopathy, and myalgia. Arthritis, neurological disease, and cardiac disease may be later stage manifestations. Erythema migrans has also been seen in patients with B. mayonii infection, but diffuse rashes are more commonly reported.(2) The chronic skin condition, acrodermatitis chronicum atrophicans, is also associated with B 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.(6) However, serology may not be positive until 1 to 2 weeks after onset of symptoms, and may show decreased sensitivity for detection of infection with B 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 Lyme-associated rashes and also be used to detect Borrelia DNA from synovial fluid and synovium biopsies. Less commonly, Borrelia DNA can be detected in cerebrospinal fluid.(7) 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.(8) The Mayo Clinic Lyme PCR test detects and differentiates the main causes of Lyme disease in North America (B burgdorferi and B mayonii) and Europe (B afzelii and B garinii).(2,7)
Supporting the diagnosis of Lyme disease in conjunction with serologic testing
Specific indications including testing skin biopsies when a rash lesion is not characteristic of erythema migrans, and testing synovial fluid or synovium to support the diagnosis of Lyme arthritis
A positive result indicates the presence of DNA from Borrelia burgdorferi, B mayonii, B afzelii, or B garinii, the main 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.
Testing of CSF by PCR in patients with suspected Lyme neuroborreliosis should be requested only on patients with positive B 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).
Concurrent infections with multiple tick-borne pathogens, including Ehrlichia muris eauclairensis, Anaplasma phagocytophilum, Babesia microti, and B 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 most members of the Borrelia burgdorferi sensu lato complex, including B andersonii, B americana, and B bissettii, which have been rarely detected in humans. Detection of DNA from these organisms would be reported as an atypical result and prompt additional laboratory testing to further identify the DNA present. The sensitivity of this assay for detecting these organisms has not been determined.
This assay also detects some members of the B 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, DK, et al: Identification of a novel pathogenic Borrelia species causing Lyme borreliosis with unusually high levels of spirochetemia: a descriptive study. Lancet Infect Dis 2016 May;16(5):556-564
3. Pritt BS, Respicio-Kingry LB, Sloan LM, et al: Borrelia mayonii sp. nov., a member of the Borrelia burgdorferi sensu lato complex, detected in patients and ticks in the upper midwestern United States. Int J Sys Evol Microbiol 2016;66(11):4878-4880
4. 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
5. 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
6. 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
7. 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
8. 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