Borrelia is a genus of the spirochete phylum. The disease caused by the bacteria is called Lyme disease.

Borrelia is a genus of the spirochete phylum. The disease caused by the bacteria is called Lyme disease.


The lab test detect two types of antibodies – IgM and IgG.

  • Borrelia IgM antibodies are generally detectable in the blood after about 2-3 weeks to the exposure of the bacteria. IgM level increases to the maximum within six weeks and then starts to decrease.
  • IgG antibodies are detectable after several weeks of exposure and reach the max level in about 4-6 months. The level tends to stay high for several years.

Borrelia1The Centers for Disease Control and Prevention (CDC) provides a recommendation for 2 different methods to detect the antibodies and confirm the diagnosis of Lyme disease. The first one is highly sensitive and can identify Lyme disease in almost all the cases. However, the result is also positive when the person is affected by any other disease like tick-borne diseases or the autoimmune disorder (lupus etc.). Therefore, for confirmation of the findings, the second method is followed.


If a patient shows the symptoms that suggest an infection with Borrelia. It is also important to know whether the patient lived or recently visited places where deer ticks are common. This increases the chance of getting infected by Borrelia.

Here are some common symptoms of Lyme disease.

  • Fever, chills
  • Fatigue
  • Muscle & joint pains
  • Swollen lymph nodes
  • Headache

If  ignored, Lyme disease may cause these problems.Borrelia

  • Severe headaches (meningitis) and neck stiffness
  • Pain and weakness in legs and arms
  • Spells of dizziness or shortness of breath
  • Change in sleep patterns, memory loss, and difficulty on concentrating
  • Irregular muscle and joint pain

The patient has to be diagnosed by Enzyme immunoassay (EIA) or immunofluorescence (IFA) tests. If the first test result is positive/intermediate, then the second test is performed – Western blot testing.

If the patient is highly suspected of Lyme disease but the reports are negative, then the patient has to be diagnosed again after a few weeks. The healthcare provider also has to be aware that if the patient didn’t have any history of a tick bite or didn’t visit the regions recently, or the symptoms don’t follow up with the typical Lyme disease symptoms, the possibility of Lyme disease can be ruled out.



IgM Antibody IgG Antibody Western Blot Possible Interpretation
Positive Positive Positive Most possibly Lyme disease, if other symptoms & signs match
Positive Negative Negative Early infection or a false-positive IgM test for cross-reactive antibodies
Negative Positive Positive Previous/late infection
Negative Negative (if IgM and IgG are negative, generally not tested) No infection. Symptoms may indicate other diseases or antibody level is too low to detect
Negative Positive Negative Patient recovered from any recent infection or false-positive IgG test for cross-reactive antibodies



Once someone gets Lyme disease, there will be the detectable amount of Borrelia IgG antibodies present in the bloodstream for the rest of the patient’s life.

Borrelia belongs to the bacteria class called spirochetes. Other spirochete diseases can result in a false-positive test, like leptospirosis and syphilis. Other diseases may also cause a false-positive test, like mononucleosis, HIV infection and various autoimmune disorders.

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