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Lyme Disease Serology

Lyme disease is caused by the spirochetes Borrelia burgdorferi and Borrelia garinii. It is the most common tick-borne infection in the United States and in Europe. In the U.S., Lyme disease is endemic in the Northeast, upper Midwest, and northern California. The blacklegged deer tick, Ixodes scapularis, is the vector of Lyme disease in the eastern and upper midwestern United States. The western blacklegged tick, I. pacificus, is the vector of Lyme disease on the Pacific Coast. Peak incidence for the onset of illness occurs in July.

Lyme disease has been a nationally notifiable condition in the United States since 1991. More than 30,000 Lyme disease cases are confirmed each year in the U.S., but the Centers for Disease Control and Prevention (CDC) estimates that approximately 300,000 cases of presumed Lyme disease go unreported each year.

A B. burgdorferi carrying tick must be attached for at least 36 hours for the bacteria to be efficiently transmitted to an individual. Following transmission, the incubation period is typically 7 to 14 days, but can range from 3 to 32 days. The first phase of infection is the appearance of an erythema migrans rash, which occurs in approximately 90% of individuals. Some patients may also experience fatigue, malaise, myalgia, headache, and lymphadenopathy. During the next few weeks, untreated individuals may develop neurologic disease including facial nerve palsy, lymphocytic meningitis, and motor or sensory radiculoneuropathy. Other extracutaneous manifestations include oligoarticular arthritis involving the large joints and myocarditis with atrioventricular heart block. Patients who are treated early with appropriate antibiotics usually experience full recovery.

Since 2008, a confirmed case of Lyme disease is defined as either 1) erythema migrans in a person who had possible exposure to tick habitat in an area where Lyme disease is endemic or who had laboratory evidence of infection or 2) at least one other defined clinical manifestation of Lyme disease in a person and laboratory evidence of infection. A probable case of Lyme disease is defined as laboratory evidence of infection in a person who had Lyme disease diagnosed by a clinician but with accompanying clinical information that does not meet the clinical criteria for a confirmed case.

Because the signs and symptoms of Lyme disease may be nonspecific, serologic tests may be helpful in confirming the diagnosis. Antibody testing is recommended only to support clinical diagnosis for patients with symptoms or signs of Lyme disease other than erythema migrans, including disseminated and late disease. Clinical evidence for neuroborereliosis, myocarditis, pericarditis, and arthritis are indications for testing. Patients presenting with chronic nonspecific symptoms should not be tested.

The Centers for Disease Control and Prevention (CDC) recommends a 2-step approach for the serologic diagnosis of Lyme disease. The first tier consists of an enzyme immunoassay (EIA) for IgG and IgM antibodies to Borrelia burdorferi. Several screening EIA are available that differ in their antigenic composition. Some use a whole cell Borrelia burgdorferi sonicate while others use a recombinant C6 peptide for antibody detection. These enzyme immunoassays can detect antibodies to all members of the Borrelia burgdorferi complex.

Sensitivity of any of the screening EIAs is only 70 to 75% in patients with early Lyme disease, but increases to approximately 90% during later stages of disease. For this reason, patients with erythema migrans should not be tested. Sensitivity of Lyme EIAs is 87 to100% for patients exhibiting later stage extracutaneous manifestations of Lyme disease such as arthritis, neurologic disorders and myocarditis. Early administration of antibiotics may weaken or delay the antibody response.

Specimens that test negative on initial screening do not need further testing. In the original two step approach, specimens testing positive by either method were confirmed with a Western blot immunoassay that contained 3 antigens on the IgM blot and 10 antigens on the IgG blot. CDC required reactivity with at least 2 IgM bands and 5 IgG bands for a Western blot to be considered positive.

In 2019, a new two-step algorithm was proposed in which the Western blot was replaced by a second EIA that was different than the first tier EIA. On July 29, 2019, FDA cleared several Lyme disease enzyme immunoassays that could be run concurrently or sequentially. FDA granted clearance to ZEUS Scientific for their ZEUS ELISA Borrelia VlsE1/pepC10 IgG/IgM Test System, ZEUS ELISA Borrelia burgdorferi IgG/IgM Test System, ZEUS ELISA Borrelia burgdorferi IgM Test System, and the ZEUS ELISA Borrelia burgdorferi IgG Test System.

Specificity of the 2-tiered testing algorithm, regardless of what screening EIA is used, is high, over 99% in both healthy individuals and those with other infectious or inflammatory diseases.

The use of serologic tests for Lyme disease for screening patients with a low probability of having Lyme disease results in a large number of false-positive results. Even with highly accurate Lyme tests, ordering of Lyme disease testing for individuals who live in nonendemic areas or who have only nonspecific symptoms, such as pain or fatigue, will result in the vast majority of positive results being falsely positive, because the predictive value of a positive result is low in this setting.

Borrelia miyamotoi, a member of the relapsing fever group of Borrelia, was first reported to cause human disease in the United States in 2013. It is transmitted by the same tick species that transmit Lyme disease. Patients infected with B miyamotoi may be misdiagnosed as having Lyme disease because this infection may cause positive results with EIA used to diagnose Lyme disease.

Specimen requirement is one SST tube of blood.


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Association of Public Health Laboratories, Suggested reporting, language, interpretation and guidance regarding Lyme Disease serologic test results, May 2021, Suggested Reporting Language, Interpretation and Guidance Regarding Lyme Disease Serologic Test Results (

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