Yes, but the test works best if you wait

Doctors can test for Lyme disease, but the timing matters more than most people realize. A blood test taken in the first week after a tick bite will often come back negative even if you have Lyme disease, because your body hasn't yet made enough antibodies for the test to detect. The standard approach is to wait one to two weeks after symptom onset, then order a two-step blood test that looks for antibodies your immune system produces in response to the bacteria.

If you have the characteristic bull's-eye rash (erythema migrans), many doctors will start treatment without waiting for test results, because the rash itself is considered diagnostic. Testing is more useful when symptoms are unclear or when the rash is absent or hard to see.

Key Takeaways

  • The standard Lyme disease test is a two-step blood test: an ELISA screening followed by a Western blot confirmation if the first test is positive.
  • Testing is most reliable one to two weeks after symptoms start; testing too early often produces false negatives.
  • A bull's-eye rash is considered diagnostic on its own, and doctors often treat without waiting for blood test results.
  • No single test can rule out Lyme disease with certainty, so your doctor will also consider your symptoms, location, and tick exposure history.

The two-step blood test process

The standard test for Lyme disease uses a method called ELISA (enzyme-linked immunosorbent assay) as the first step. This test detects antibodies to Borrelia burgdorferi, the bacterium that causes Lyme disease. If the ELISA comes back positive or borderline, your doctor will order a Western blot as confirmation. The Western blot is more specific and helps rule out false positives from other infections or conditions.

This two-step approach is the standard recommended by the Centers for Disease Control and Prevention (CDC). A single positive ELISA without Western blot confirmation is not considered reliable enough to diagnose Lyme disease, because other infections can trigger a positive ELISA result.

Your doctor will draw blood from your arm and send it to a lab. Results typically come back within a few days to a week, depending on the lab and whether both tests are needed.

Why timing affects your test results

During the first week of infection, your body is still mounting an immune response. Antibodies take time to develop—usually at least seven to ten days after the tick bite, and sometimes longer. A test done too early will miss the infection because there are not yet enough antibodies to detect.

This is why doctors sometimes recommend waiting before testing if symptoms are mild or if you are unsure whether you were actually infected. Testing at day three or four after a bite is unlikely to help and may delay diagnosis if you test negative and then stop looking for other explanations.

Once antibodies are present, they can remain detectable for months or even years after successful treatment. A positive test does not always mean you have active Lyme disease—it can mean you were infected in the past. Your doctor will use your current symptoms and the test result together to decide whether to treat.

When doctors diagnose without a test

The bull's-eye rash (erythema migrans) is considered diagnostic for Lyme disease on its own. If you have this rash and live in or recently visited an area where Lyme disease is common, your doctor may start treatment immediately without waiting for blood test results. The rash typically appears three to thirty days after a tick bite and expands outward in a circular pattern, often with a clear center.

Not everyone with Lyme disease develops the rash, and not everyone who develops it seeks medical care right away. In these cases, blood tests become more important for diagnosis. Your doctor will also consider whether you remember a tick bite, whether you live in a high-risk area, and what other symptoms you have.

Tests that are not reliable for Lyme disease

Several tests are marketed for Lyme disease but are not recommended by the CDC or major medical organizations. Lyme disease urine antigen tests have not been validated and are not considered reliable. CD57 count tests (which measure a type of white blood cell) are sometimes promoted as a way to diagnose or monitor Lyme disease, but there is no scientific evidence that they work for this purpose.

Some labs offer tests for co-infections that may be transmitted by the same tick—such as Babesia or Ehrlichia—but these should only be ordered if you have symptoms suggesting those infections. Testing for co-infections when you have no symptoms of them is not standard practice and can lead to unnecessary treatment.

If you have had a test done at a lab that is not accredited by the Clinical Laboratory Improvement Amendments (CLIA), or if you received results that seem unusual, ask your doctor whether the test meets standard medical guidelines.

What to do if your test is negative but symptoms persist

A negative Lyme disease test does not always rule out Lyme disease, especially if you tested too early or if you have symptoms that started more than a month ago. If your symptoms fit the pattern of Lyme disease—such as expanding rash, joint pain, or neurological symptoms—and you live in an area where Lyme disease is common, your doctor may recommend treatment even with a negative test.

Some people have symptoms that resemble Lyme disease but are caused by something else entirely. Your doctor may order additional tests to look for other conditions, such as rheumatoid arthritis, fibromyalgia, or other tick-borne infections. Keeping a record of when your symptoms started, what they feel like, and whether they change over time will help your doctor narrow down the cause.

Where Lyme disease is most common and why it matters for testing

Lyme disease is concentrated in certain parts of the United States. The Northeast (particularly New England and the Mid-Atlantic states), the Upper Midwest, and parts of the Pacific Coast have the highest rates. If you live in or visited one of these areas in the months before your symptoms started, your doctor is more likely to consider Lyme disease as a diagnosis and to interpret a borderline test result as positive.

If you live in an area where Lyme disease is rare and have no history of travel to a high-risk area, a positive test is more likely to be a false positive. Your doctor will take geography into account when deciding whether to treat based on test results alone.

Frequently Asked Questions

Can I test for Lyme disease right after a tick bite?

Testing immediately after a tick bite is not useful because antibodies have not yet developed. Most doctors recommend waiting one to two weeks after symptoms appear before testing. If you are worried about infection, talk to your doctor about whether preventive treatment makes sense in your situation.

How long does it take to get Lyme disease test results?

Results from the first test (ELISA) usually come back within a few days. If that test is positive or borderline, the Western blot confirmation may take another few days to a week. Some labs are faster than others, and results may take longer during busy periods.

If I test positive for Lyme disease, does that mean I need treatment?

A positive test combined with symptoms that fit Lyme disease usually means treatment is recommended. However, a positive test alone—without current symptoms—does not always require treatment, because antibodies can persist for years after successful treatment in the past. Your doctor will consider your symptoms and when they started.

Can Lyme disease be cured?

Early Lyme disease is treated with antibiotics and most people recover fully. Late Lyme disease (involving joints or the nervous system) also responds to antibiotics, though recovery may take longer. Some people report lingering symptoms after treatment, though the reason for this is not fully understood.

What should I do if I find a tick on my skin?

Remove the tick as soon as you notice it by grasping it close to the skin with tweezers and pulling straight out. Clean the area with soap and water or rubbing alcohol. Save the tick in a sealed bag if possible, in case you develop symptoms and your doctor wants to know what kind of tick it was. Watch for a rash or symptoms over the next month.