Introduction
Lyme disease is a tick-borne illness caused primarily by the bacterium Borrelia burgdorferi. While early treatment is highly effective, diagnosis can be tricky—especially if you don’t have the telltale bullseye rash. That’s where testing comes in.
But Lyme disease tests aren’t always straightforward. They vary in accuracy depending on the stage of the disease, and interpreting results can be challenging. In this article, we’ll break down the types of Lyme disease tests, their limitations, and how they’re used during different stages of infection.
How Lyme Disease Progresses (Why Stage Matters in Testing)
Lyme disease progresses in three stages:
- Early Localized (Days 3–30)
- Bullseye rash (erythema migrans)
- Flu-like symptoms
- Antibodies may not yet be detectable
- Early Disseminated (Weeks to Months)
- Facial palsy, multiple rashes, joint pain
- Antibodies begin to appear in blood
- Late Disseminated (Months to Years)
- Arthritis, neurological symptoms, fatigue
- Antibodies are usually detectable and stable
Key point: Most tests detect antibodies produced by your immune system—not the bacteria itself—so results depend heavily on timing.
Types of Lyme Disease Tests
1. Two-Tiered Antibody Testing (Standard Method)
The CDC recommends a two-step approach:
Step 1: Enzyme Immunoassay (EIA) or Immunofluorescence Assay (IFA)
- A screening test to detect antibodies to Borrelia burgdorferi.
- If negative → Lyme disease unlikely.
- If positive or equivocal → move to Step 2.
Step 2: Western Blot
- Confirms the presence of IgM (early) and IgG (later) antibodies.
- Looks for specific patterns of antibody response.
Limitations:
- False negatives are common early on (first 2–4 weeks).
- IgM may cause false positives after a few months.
- Positive IgG may persist even after successful treatment—not a sign of active infection.
2. PCR (Polymerase Chain Reaction)
- Detects bacterial DNA in fluid (e.g., joint fluid, cerebrospinal fluid).
- Most useful in late-stage Lyme with arthritis or neurological symptoms.
- Rarely used for blood testing due to low bacterial load.
Not sensitive to early disease, and a negative result doesn’t rule it out.
3. Culture
- Attempts to grow B. burgdorferi from a sample.
- Time-consuming and not routinely available.
- Used more often in research than clinical settings.
When Should You Get Tested?
| Scenario | Test Recommended? | Reason |
| Bullseye rash (EM) | ❌ No | Diagnosis is clinical; early test may be falsely negative |
| No rash but flu-like symptoms + tick exposure | ✅ Yes | Antibody tests can support diagnosis |
| Joint pain months after a tick bite | ✅ Yes | IgG likely detectable |
| Symptoms within days of bite | ❌ No (or delayed) | Antibodies likely not present yet |
Common Misunderstandings About Lyme Testing
Myth 1: A negative test means you don’t have Lyme disease.
Fact: If done too early, antibody levels may not be high enough to detect.
Myth 2: A positive test means you currently have Lyme.
Fact: Antibodies can remain long after the infection is treated. Tests can’t distinguish between past and active infections.
Myth 3: All labs use the same testing standards.
Fact: Not all tests are FDA-approved. Some specialty labs offer unvalidated tests with questionable accuracy. Always verify the test used.
What About At-Home Lyme Tests?
Some companies offer mail-in Lyme disease test kits. While convenient, they:
- May not follow CDC-approved two-tiered testing
- Could yield false positives or negatives
- Should be followed up with confirmatory testing from a healthcare provider
Interpreting Results: When to Treat or Retest
| Test Result | Interpretation | Action |
| Negative EIA + early symptoms | Possibly too soon to detect | Monitor, retest in 2–3 weeks |
| Positive EIA + Positive IgM/IgG Western blot | Likely active or recent Lyme | Start or continue treatment |
| Positive IgG only, months after treatment | Past infection | No treatment if asymptomatic |
Conclusion
Lyme disease testing is a useful tool—but it’s not perfect. Results depend heavily on timing, symptom presentation, and test method used. The best outcomes happen when doctors use clinical judgment in combination with testing—not based on lab results alone.
If you think you may have been exposed to Lyme disease, talk to a healthcare provider. Early treatment can prevent long-term complications, even if tests are not yet conclusive.
FAQs
When should I get tested for Lyme disease?
Wait 2–4 weeks after a suspected bite for accurate antibody testing, unless you have a bullseye rash (then testing is not needed).
Can I test positive for Lyme even after treatment?
Yes. Antibodies can remain in your system for months or years, even after the bacteria are gone.
Can I rely on at-home Lyme disease tests?
Be cautious. Some lack validation. Always consult a healthcare provider for a confirmed diagnosis and treatment.
Is a PCR test better than an antibody test?
Not always. PCR is best for joint fluid or spinal fluid, not early infection in blood.
Does a negative test mean I don’t have Lyme disease?
Not necessarily—early testing may miss antibodies. A second test may be needed if symptoms persist.
