Useful For

Aiding in the diagnosis of Lyme Disease (LD).

 

Indications for Testing

 

Early localized Lyme disease does not require diagnostic testing before antibiotic therapy is started. A presumptive diagnosis can be made on the basis of the clinical presentation and a credible history of exposure to infected blacklegged vector ticks.

 

Diagnostic testing is appropriate for people with a history of tick exposure and symptoms of disseminated LD. Borrelia burgdorferi is the causative agent of LD. Test sensitivity improves as the agent affects tissue systems other than the skin. However, testing should be limited to those with objective signs of infection. Please refer to the table below.

 

Stage  of Infection	Recommended   Clinical Management and Testing Strategy	Specimens   of Choice for Diagnostic Testing
Erythema   migrans, acute phase-Seasonal occurrence and exposure in an endemic area*	Clinical   diagnosis and empirical treatment	None
Erythema   migrans, acute phase- Out of season or no known exposure in an endemic area	2-tiered   serology** – Repeat EIA in six weeks if negative; treatment at   physician’s discretion.***	Serum,   Plasma,  Biopsy
Characteristic   neurological, cardiac or joint involvement	2-tiered   serology**	Serum,Synovial   fluid or CSF
Persistent   symptoms following recommended treatment	None	None

 

^*Endemic areas are localities where blacklegged ticks are established and B. burgdorferi cycles of transmission are maintained.

^**Where appropriate, EIA is followed by confirmatory WB using diagnostic kits licensed in Canada.

^***NAAT or bacterial culture  are not generally performed.

 

 

Group Test Information

 

Test Code	Reporting Name	Available Separately	Always Performed
BBURABGM	B. BURGDORFERI Ab IgG + IgM	No	Upon request
BBURDCFP	B. BURGDORFERI DNA;CSF;PCR	No	Upon request

 

 

Recommended Testing Approach

 

The immune response to B. burgdorferi infection begins with the appearance of IgM antibodies, usually within two weeks of a vector tick bite. These antibodies may persist for months or even years despite effective antimicrobial therapy. Following  IgM response IgG antibodies develop in most patients, typically after one month of infection.

 

A two-tiered serology testing is recommended for LD diagnosis. This consists of an enzyme immunoassay (EIA) screening followed by confirmation with Western blot (WB) testing for the detection of IgM and or IgG antibodies. When the above tests are performed in sequence the overall sensitivity and specificity are maximized.

 

 

Serology provides a snapshot of the immune status of the patient at the time of the specimen collection. For instance, if LD is suspected on the basis of symptoms but early serological testing is negative, follow-up testing on a convalescent sample is recommended.

 

 

EIA

EIAs are used as screening tests to detect IgM andor IgG antibodies that are directed against B. burgdorferi.  EIAs rely on the use of whole-cell preparations of B. burgdorferi andor recombinant antigens. While most EIAs are highly sensitive they may lack specificity, in that false positives results can occur due to other medical conditions.

 

 

WB

WB is used as the confirmatory test as it has greater specificity than EIA. WB detects IgM and or IgG antibodies that are directed against electrophoretically separated antigen extracts and recombinant antigens native to B. burgdorferi, and can differentiate IgM from IgG antibodies. A positive WB result is required to confirm exposure to B. burgdorferi. Demonstration of seroconversion from IgM to IgG antibodies by WB provides definitive evidence of a recent infection.

 

 

Two Tier Testing Algorithm                                                                                                          

Special Instructions For Ordering Tests

The following must be provided:

1.      Detailed travel history and date of onset of symptoms – This should be included on the requisition as it helps to apply the most appropriate testing algorithm.

2.       History of antibiotic treatment – This can compromise the immune response to infection and may affect the interpretation of test results.

3.      Presence of other infections or pre-existing conditions – Infection with other related pathogens (e.g. syphilis) and autoimmune disorders as these may lead to false-positive results.

4.      Prior history of laboratory-confirmed LD– This is important as there is no pattern of serological response that can differentiate re-infection from an initial infection with B. burgdorferi.

 

Test Method Name

Serology

Enzyme Immunoassay (EIA)
Western Blot (WB)

 

Reporting Name

B. BURGDORFERI Ab IgG + IgM

Lyme IgG/IgM EIA

Lyme IgG Western Blot

Lyme IgM Western Blot

B. BURGDORFERI DNA

Lyme PCR

 

Ordering Mnemonic

BBURABGM

BBURDCFP

 

Aliases

 

B. burgdorferi

Borrelia burgdorferi

Lyme

Soft-CLYME

Tick-borne