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Lyme Disease IgG Antibody, Qualitative

Published: August 9, 2026Updated: August 17, 2026

A blood test that detects IgG antibodies to the bacterium that causes Lyme disease.

Quick summary

["A positive result shows exposure to Lyme bacteria, but it may reflect a past infection rather than active disease."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
21370-2
Short code
Deprecated Lime IgG RAST Ql
Synonyms
Deprecated Lime IgG RAST Ql
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84484
SNOMED
302774002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test looks for Lyme disease IgG antibodies in a blood sample. IgG antibodies are proteins made by the immune system after exposure to the bacterium that causes Lyme disease.

Why might I need this test?

Your clinician may order this test if you have a rash, flu-like symptoms, joint pain, neurologic symptoms, or a possible tick bite or exposure to areas where Lyme disease occurs. It may also be used to evaluate symptoms that suggest an earlier infection.

How is the test performed?

A blood sample is collected and analyzed for antibodies to Lyme disease bacteria. A positive screen may be followed by another laboratory method to confirm the result.

How do I prepare for the test?

No special preparation is usually needed. Tell your clinician about recent tick bites, travel or outdoor exposure, prior Lyme disease, and any symptoms or antibiotics you have recently received, because these details can affect interpretation.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lyme IgG antibody

Frequently asked questions

Does a positive Lyme IgG test mean I have Lyme disease now?
Not always. IgG antibodies can remain detectable for years after a past infection, so a positive result may reflect previous exposure rather than active illness.
Can a negative result rule out Lyme disease?
A negative result may make Lyme disease less likely, especially when symptoms and exposure history fit. Early infection may not yet have produced detectable antibodies, and another test or repeat testing may sometimes be needed.
What symptoms or exposure should I discuss with my clinician?
Mention any expanding rash, fever, headache, fatigue, joint swelling, facial weakness, or nerve symptoms, as well as tick bites and time spent in wooded or grassy areas where Lyme disease is common.
  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 17, 2026. · Read our editorial policy