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Borrelia burgdorferi IgG and IgM Antibody Serology (Serum) by Titration

Published: August 9, 2026Updated: August 15, 2026

This test measures the levels of antibodies against *Borrelia burgdorferi*, the bacterium responsible for Lyme disease, in your blood. Antibodies are your body’s immune response to infection.

Quick summary

["Helps diagnose Lyme disease by detecting past or current infection."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
104380-1
Short code
COXQ2
Synonyms
C burnet IgM sp2 Titr Ser IA
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) - red-top or gold-top (tiger-top) tube; alternatively, plain red-top tube without anticoagulant
Units
N/A
Ref low
100
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Enzyme-linked immunosorbent assay (ELISA) or chemiluminescent immunoassay (CLIA) for detection of IgM antibodies to Coxiella burnetii phase II antigen
CPT
86638
SNOMED
313580003
Specimen volume
1-2 mL serum (minimum 0.5 mL); collect 5-10 mL whole blood in SST tube
Stability
Serum stable at room temperature (15-25°C) for 8 hours; refrigerated (2-8°C) for 7 days; frozen at -20°C or below for up to 4 weeks. Avoid repeated freeze-thaw cycles. For prolonged storage, aliquot and store at -70°C.
Hemolysis max
200
Lipemia max
100
Icterus max
40
TAT
24–72 hours
Order
routine

What Does This Test Measure?

The test looks for two types of antibodies—IgG and IgM—that your immune system produces when exposed to *Borrelia burgdorferi*. IgM antibodies appear early in infection, while IgG antibodies develop later and can persist longer. The test also measures the **titer** (concentration level) of these antibodies, which helps determine if the infection is active or resolved.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fever, rash (e.g., bull’s-eye rash), joint pain, or neurological issues that could suggest Lyme disease. It’s also used in follow-up testing after suspected exposure or treatment.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The serum (liquid part of blood) is then tested in a lab to measure antibody levels using a **titration method**, which compares antibody concentrations at different dilutions.

What Are Common Symptoms?

Lyme disease symptoms vary but may include flu-like illness (fever, chills), a rash (erythema migrans), muscle aches, fatigue, or neurological problems (headaches, numbness). Antibody tests help confirm infection, but symptoms alone aren’t diagnostic.

Reference range

Titer <1:100: Negative - No significant level of IgM antibody detected; Titer 1:100-1:200: Equivocal/Borderline - Recommend repeat testing in 2-4 weeks; Titer ≥1:200: Positive - Suggests recent or acute Q fever infection. Paired serology (2nd specimen) demonstrates fourfold or greater rise in IgM titer compared to acute-phase specimen, confirming seroconversion.N/A

Specimen: serum

No special patient preparation required. No fasting necessary. Specimen should be collected prior to initiation of antibiotic therapy when possible, as early treatment may blunt antibody response. Second (convalescent) specimen should be collected 2-4 weeks after the acute-phase specimen to demonstrate seroconversion.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Borrelia Antibody Titers

Frequently asked questions

How soon after exposure can you get tested?
IgM antibodies may appear within 1–4 weeks after infection, while IgG antibodies can take weeks to months to develop. Early testing may miss IgM antibodies, so results can be delayed if symptoms are recent. Your provider will guide timing based on your symptoms and exposure history.
What does a positive result mean?
A positive test indicates past or current infection, but false positives can occur (e.g., from other infections or prior vaccination). If results are positive, further testing (e.g., confirmatory assays) may be needed to confirm Lyme disease diagnosis.
Can this test detect Lyme disease in early stages?
No, this test primarily detects antibodies, not the live bacterium. Early Lyme disease may not show detectable antibodies yet. If symptoms persist, your provider may recommend additional tests (e.g., PCR or culture) or retesting after treatment.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy