Lyme Antibody (IgG) Biomarker Test Guide

Lyme Antibody (IgG) Biomarker Test Guide

The Lyme Antibody (IgG) Test is a blood test that detects antibodies produced by the immune system in response to an infection caused by the bacterium Borrelia burgdorferi, which leads to Lyme disease. This test measures IgG antibodies, which develop later in the infection and typically indicate an established or past infection.

What Is the Lyme Antibody (IgG) Test?

Lyme disease is transmitted to humans through the bite of an infected black-legged tick (also known as a deer tick). When the body is exposed to the bacteria, the immune system produces antibodies to fight off the infection. There are two types of antibodies measured in Lyme disease testing:

  • IgM: Produced early in the infection, generally within 1–2 weeks after the tick bite.
  • IgG: Appears later in the course of infection, often 4–6 weeks after exposure, and can remain in the body for months to years.

The Lyme Antibody (IgG) Test is often part of a two-step process to confirm Lyme disease:

  1. Enzyme-linked immunosorbent assay (ELISA): The initial screening test to detect antibodies.
  2. Western Blot: A confirmatory test to ensure the specificity of the antibodies detected by ELISA.

Why Get a Lyme Antibody (IgG) Test?

The Lyme Antibody (IgG) Test is recommended if you:

  • Have been bitten by a tick in an area where Lyme disease is common.
  • Are experiencing symptoms of Lyme disease, particularly after possible tick exposure.
  • Are undergoing evaluation for Lyme disease treatment or monitoring for disease progression.

Common Symptoms of Lyme Disease Include:

  • Early Stage:
    • Erythema migrans (bull’s-eye rash): A red, expanding rash that often appears at the site of the tick bite.
    • Flu-like symptoms: Fatigue, headache, fever, muscle aches, and chills.
  • Late Stage (if left untreated):
    • Joint pain: Particularly in the knees.
    • Neurological symptoms: Such as facial palsy, numbness, or tingling in the extremities.
    • Heart problems: Like Lyme carditis, causing irregular heartbeats.

What Are the Normal Ranges?

  • Negative: A negative IgG test suggests that you do not have a significant Lyme infection or that it is too early to detect an IgG response.
  • Positive: A positive result indicates a past or ongoing infection with Borrelia burgdorferi.

Important Note: Since IgG antibodies can persist for months or years after infection, a positive result may not necessarily indicate an active infection. Clinical evaluation, symptoms, and other tests should be taken into account to confirm a diagnosis.

Related Health Symptoms

Symptoms that may prompt a healthcare provider to order a Lyme Antibody (IgG) Test include:

  • A history of tick exposure or a known tick bite.
  • Development of a bull’s-eye rash.
  • Flu-like symptoms, especially if they occur within weeks of a tick bite.
  • Persistent fatigue, joint pain, or neurological symptoms such as facial weakness or difficulty concentrating.

What Type of Health Professionals Can Use the Results?

  • Primary Care Physicians: Typically the first to order the test when Lyme disease is suspected.
  • Infectious Disease Specialists: Experts in treating Lyme disease, particularly in complicated or long-standing cases.
  • Rheumatologists: May be involved when Lyme disease causes joint pain or swelling, resembling arthritis.
  • Neurologists: Specialists who manage neurological complications from Lyme disease, such as facial palsy or cognitive issues.
  • Cardiologists: In cases where Lyme disease affects the heart, particularly when Lyme carditis is suspected.

How Often Should the Test Be Taken?

  • Initial Diagnosis: The test is usually performed once if Lyme disease is suspected based on symptoms and possible tick exposure.
  • Follow-up Testing: Repeat testing may not be necessary if an initial diagnosis is confirmed, but in chronic or relapsing cases, further evaluation may be required.
  • Monitoring Treatment: In some cases, a physician may order additional tests to monitor the effectiveness of treatment, although antibody levels may not change significantly with treatment.

What’s the Next Step After Testing?

The next steps after receiving Lyme Antibody (IgG) test results depend on the outcome:

  1. Negative Result:
    • If symptoms persist but the test is negative, it may be too early in the infection for IgG antibodies to appear. In such cases, a follow-up test may be ordered.
    • Other diagnostic tests or medical evaluations may be needed to rule out other conditions.
  2. Positive Result:
    • If the IgG test is positive and symptoms suggest Lyme disease, treatment with antibiotics may be initiated.
    • Further tests like the Western Blot may be ordered to confirm the diagnosis.
    • Additional medical evaluations may be necessary if complications (e.g., neurological or cardiac) are suspected.

Top 5 Questions Related to Lyme Antibody (IgG) Tests and Results

  1. How soon after a tick bite should I take the Lyme Antibody (IgG) test? IgG antibodies typically take 4–6 weeks to develop, so the test is more useful for detecting late-stage or past infections. For early diagnosis, an IgM antibody test or clinical evaluation might be more appropriate.
  2. Can I have Lyme disease if my IgG test is negative? Yes, if the infection is recent, IgG antibodies may not have developed yet. A negative IgG test in the early stages does not rule out Lyme disease. An IgM test or repeat testing may be needed.
  3. What should I do if my Lyme IgG test is positive but I don’t have symptoms? A positive test may indicate a past infection, even if you’re asymptomatic. In such cases, no treatment is needed unless symptoms or complications develop. Your doctor may monitor you or recommend further tests if necessary.
  4. Can the Lyme Antibody (IgG) test be falsely positive? Yes, false positives can occur, particularly in individuals with other infections or autoimmune diseases. Confirmatory testing (e.g., Western Blot) is often used to ensure accuracy.
  5. Can Lyme antibodies disappear after treatment? IgG antibodies may persist for months or even years after successful treatment, even if the infection is resolved. A decrease in symptoms and improvement in health are more reliable indicators of successful treatment than changes in antibody levels.

 


The Lyme Antibody (IgG) Test is an important diagnostic tool for detecting past or ongoing infections with Borrelia burgdorferi, the bacterium that causes Lyme disease. While a positive result indicates exposure to the bacteria, clinical evaluation is essential to confirm an active infection and determine the need for treatment. Health professionals, including primary care physicians, infectious disease specialists, and rheumatologists, use this test to diagnose and manage Lyme disease. The test is most effective in diagnosing later stages of Lyme disease or monitoring past infections, with treatment depending on the severity of symptoms and disease progression.  

This guide provides key insights into understanding Lyme Antibody (IgG) testing, what to expect, and how it fits into the larger diagnostic picture for Lyme disease.


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Disclaimer: The information provided in these articles is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare professional before making any decisions about your health or starting any treatments.

 

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