Lyme Disease Tests: Science vs Misconceptions

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Lyme diagnosis and testing can be very confusing. This confusion has contributed to false positive diagnoses and unnecessary treatment.

As in other infections like HIV, testing for Lyme disease involves looking for antibodies produced by the body’s immune system in response to infection. This is called serologic testing because the antibodies are found in blood serum.

Testing positive for antibodies is called seropositive and testing negative for antibodies is called seronegative.

Lyme disease testing: Useful when performed appropriately

One known problem is that we can produce antibodies for years or decades after a Lyme infection has been eradicated. Therefore, a seropositive test on its own is not necessarily indicative of active infection.

In addition, it can take a few weeks for detectable antibodies to build up in the body. Pseudoscience advocates frequently mislead about Lyme antibody testing by failing to differentiate testing performance in early infection from testing performance in late infection.

Below is a CDC-produced illustrative example of antibody production in Lyme disease, which triggers a positive test once a detection threshold is reached.

Two types of antibodies are shown: IgG and IgM. Typically, a detectable IgM antibody response is produced first, followed by a detectable IgG response.

Some guidelines from CDC:

  • Patients who have had Lyme disease for longer than 4-6 weeks, especially those with later stages of illness involving the brain or the joints, will almost always test positive.
  • A patient who has been ill for months or years and has a negative test almost certainly does not have Lyme disease as the cause of their symptoms.
  • Serologic testing is generally not useful or recommended for patients with single EM rashes. For this manifestation, a clinical diagnosis (alone) is recommended.

Since IgG antibodies are detectable after 4-6 weeks of infection, experts echoed CDC in concluding:

Immunoglobulin G (IgG) seronegativity in an untreated patient with months to years of symptoms essentially rules out the diagnosis of Lyme disease, barring laboratory error or a rare humoral immunodeficiency state.

Beware IgM false positives

IgM Lyme testing is notorious for producing false positive results, which is why it is only used in very limited circumstances, i.e. during the first 30 days of illness before detectable IgG antibodies would be produced in the event of a Lyme infection.

The CDC diagnosis and testing page states:

Positive IgM results should be disregarded if the patient has been ill for more than 30 days.

The CDC Lyme FAQ addresses how to interpret long-lasting symptoms where an IgG test was negative but the IgM test was positive:

If you have been infected for longer than 4 to 6 weeks and the IgG Western Blot is still negative, it is highly likely that the IgM result is incorrect (e.g., a false positive). This does not mean that you are not ill, but it does suggest that the cause of illness is something other than the Lyme disease bacterium.

Experts agree around the world

A strong scientific consensus is evident about Lyme disease diagnosis and testing.

A 2018 French review of 16 Lyme diagnostic guidelines from 7 countries “revealed a global consensus regarding diagnosis at each stage of the infection.” The only outlier was the pseudoscience group German Borreliosis Society (Deutsche Borreliose-Gesellschaft, DBG), a German counterpart to the pseudoscience group ILADS.

Independent studies show testing accuracy in late stage

A 2016 systematic review [8] that included 8 studies of CDC-recommended two tier test performance in “Late Lyme” showed Lyme antibody testing to be 99.4% sensitive and 99.3% specific** in North America. 

In other words, out of 100 people with Late Lyme disease, 99-100 of them will test positive. Out of 100 people who may believe they have Late Lyme disease but do not, 99-100 of them will test negative.

Misinformation can convince patients to ignore or misinterpret negative tests to justify a false “Chronic Lyme” diagnosis.

Photo of girl holding a school test with failing grade. Captioned: I didn't fail the test. I got a few right, which means I passed.
Misinterpreting or ignoring a negative test can result in false diagnoses.

Avoid unnecessary and unscientific testing

As part of the admirable “Choosing Wisely” campaign to reduce unnecessary tests and treatments, the American College of Rheumatology (ACR) warns:

Don’t test for Lyme disease as a cause of musculoskeletal symptoms without an exposure history and appropriate exam findings. [1]

The CDC [4], French Society of Internal Medicine, and other experts [22] around the world have expressed similar sentiments to the ACR.

As discussed in the CDC video below, determining the pretest probability of Lyme disease is very important:

Predatory labs: How they trick people

Experts strongly warn against unvalidated testing [5, 9].  Quackwatch [10] and Science-Based Medicine [11] both provide accessible explanations about the differences between validated, science-based tests and unvalidated tests.

In North America, only CDC-recommended and FDA-cleared or approved testing should be used. Health agencies in Canada make the same recommendations as CDC.

Sadly, a number of predatory labs exploit permissive laws surrounding “lab developed tests” to peddle testing that should not be relied upon.

Some predatory labs boast that they are CLIA-certified, but such lab certification does not mean that a test is useful. Even the notoriously fraudulent lab Theranos was CLIA certified.

CDC scientists explain:


  • CLIA certification of a laboratory indicates that the laboratory meets a set of basic quality standards.
  • It is important to note, however, that the CLIA program does not address the clinical validity of a specific test (i.e., the accuracy with which the test identifies, measures, or predicts the presence or absence of a clinical condition in a patient).
  • FDA clearance/approval of a test, on the other hand, provides assurance that the test itself has adequate analytical and clinical validation and is safe and effective.

Besides misrepresenting CLIA certification, predatory labs use other methods to trick patients, including:

  • Charging big bucks,
  • Testing for many biomarkers to maximize the chance of a non-negative result,
  • Creating proprietary diagnostic criteria, and
  • Returning indeterminate results, which will often be interpreted as positive.

How can high prices trick people? There is a well-established principal in psychology whereby we tend to rely on price as a marker of quality.

Science-based Lyme testing is generally covered by insurers and health systems, and is low-cost regardless. A CDC analysis found Lyme testing was only $42, on average. Testing from predatory labs can cost much more than science-based tests, which can mislead people into thinking they are somehow superior.

Dr. David Patrick describes how unvalidated testing—that we consider to be predatory—became so popular and why it can cause terrible consequences:

How Lyme antibody testing works

Antibody testing for Lyme disease requires two different tests to establish a positive result. If either the first tier test or the second tier test is negative, the test result is negative overall.

But in the event of a negative result, Dr. Adriana Marques of the NIH states:

For patients with signs or symptoms consistent with Lyme disease for less than or equal to 30 days, the provider may treat the patient and follow up with testing of convalescent-phase serum.

The first tier of the “two-tiered testing” system is an Enzyme Immunoassay (EIA aka ELISA).

The second tier of the well-established Standard Two-Tiered Testing (STTT) involves IgM and IgG Western Blot tests, which can be complicated to understand. The Western Blot is also called an immunoblot or a line blot.

In 2019, CDC added a second test system to its recommended tests, the Modified Two-Tiered Test (MTTT). In the MTTT, the second tier is a different ELISA that is FDA-cleared specifically for the MTTT.

By using the MTTT, testing is simpler, costs may be reduced, and Lyme disease is more likely to be detected in the first weeks of infection.

A drawback of the MTTT is that potentially useful information is no longer determined about which types of antibodies are being produced by the body.

See also: Lyme testing algorithm flow charts by Dr. Adriana Marques

More about Western Blot testing in North America

The IgG Western Blot test is designed to detect antibodies specific to Borrelia burgdorferi, the bacteria that cause Lyme disease. For Lyme disease in North America, a positive IgG Western Blot test requires at least 5 of 10 measured “bands” to be positive (or reactive).

The scored IgG bands are 18 kDa, 24 kDa (OspC)†, 28 kDa, 30 kDa, 39 kDa (BmpA), 41 kDa flagellin (Fla), 45 kDa, 58 kDa (not GroEL), 66 kDa, and 93 kDa.

The Lyme IgM Western Blot test measures 3 different types of antibodies. The North American IgM Western Blot is considered positive only if 2 of 3 IgM bands are positive (or reactive).

The scored IgM bands are 24 kDa (OspC)†, 39 kDa (BmpA), and 41 kDa (Fla).

As discussed above, the IgM Western Blot should only be used in the first 30 days of illness.

† According to CDC, “Depending upon the assay, OspC could be indicated by a band of 21, 22, 23, 24 or 25 kDA.”

Important: Don’t misinterpret a negative test as positive

Many people without Lyme disease will test positive for some bands. Therefore, CDC cautions:

It is not correct to interpret a test result that has only some bands that are positive as being “mildly” or “somewhat” positive for Lyme disease.

For example, in one study, 43% of healthy people and 75% of syphilis patients tested positive for IgG band 41. In a study of US veterans in New York, 76% of those without Lyme disease tested positive for IgG band 41. In a 1996 study, in healthy people, 55% and 21% tested positive for IgG band 41 and IgM band 41, respectively.

Even without a Borrelia burgdorferi infection, many of us produce antibodies that will react on a Lyme test. Notably, harmless bacteria found naturally in our mouths can cause us to test positive for band 41.

Both tiers are important

A positive Lyme antibody test requires both tiers to be positive, as many without Lyme infections can test positive on single tests. For example, one study found up to 40% of patients with Lupus and other rheumatic diseases test positive on the first tier ELISA test. The second tier test is necessary to stop a false positive diagnosis.

The American Society for Microbiology recommends against ordering the Western blot without a positive ELISA screening:

The Lyme immunoblot test is designed only as a confirmatory test, so it is important not to test screen-negative samples.  

LymeScience recommends against:

  • Tests from any of the following labs: IgeneX, DNA Connexions, Galaxy Diagnostics, Medical Diagnostic Laboratories (MDL), Milford Molecular Diagnostics Laboratory, Advanced Lab, Fry Laboratories, Ceres Nanosciences (Nanotrap), Global Lyme Diagnostics, Pharmasan Labs (iSpot Lyme), Coppe Laboratories (myLymeTest), ArminLabs, BCA-Lab (also known as InfectoLab), Australian Biologics, Melisa Labs, Moleculera Labs (Cunningham Panel), R.E.D. Labs, Immunosciences Lab, Aperiomics, Te?ted Oy (Tezted Limited, TICKPLEX), Lyme Diagnostics Ltd. (DualDur cell technology), ProGene (DX Genie), Ionica Sciences (IonLyme), T Lab Inc., Veramarx, Vibrant America/Vibrant Wellness, Research Genetic Cancer Centre (RGCC)/Biocentaur (PaLDiSPOT, PrimeSpot), Nordic Laboratories
  • Any lab on Quackwatch’s list of “Laboratories Doing Nonstandard Laboratory Tests
  • CD57 testing
  • Diagnosis with microscopy, e.g. Live Blood Cell Analysis.
  • Diagnosis based on magical beliefs, for example applied kinesiology a.k.a Autonomic Response Testing (ART)
  • Urine tests
  • Electrodermal testing
  • Lymphocyte Transformation Test (LTT)
  • ELISpot and interferon gamma tests
  • MELISA testing
  • Phelix Phage tests
  • Failing to follow testing strategies recommended by CDC or local infectious diseases organizations
  • Failing to perform and acknowledge both tests of the established two-tiered test
  • Using testing that is not cleared or approved by the FDA
  • Clinical diagnosis without a science-based rationale
  • Diagnosis via a questionnaire of non-specific symptoms
  • Diagnosis from an unscientific practitioner, including those who market themselves using the following terminology: Lyme literate (especially those affiliated with ILADS), integrative, functional, alternative, complementary, Traditional Chinese Medicine, holistic, natural, Biological, Ayurvedic, chiropractic, naprapathic, homeopathic, and naturopathic
  • Diagnosis from a psychic, energy healer, shaman, or practitioner of muscle testing (aka ART-Autonomic Response Testing or applied kinesiology)
  • Direct-to-consumer testing that hasn’t been ordered by a medical provider (e.g. LetsGetChecked and Everlywell)
  • Relying on Clinical Laboratory Improvement Amendments (CLIA) certification as an indication that a test result is legitimate (see CDC discussion)
  • Any testing not recommended by CDC

Additionally, LymeScience endorses guidance by the Association of Public Health Laboratories, which is in line with other experts and referenced on the CDC Lyme diagnosis and testing site:


Scenarios for which Lyme disease serologic testing is NOT recommended include:

  • Presence of erythema migrans in high incidence areas.
  • Absence of likely Ixodes tick exposure (CDC: Regions Where Ticks Live)
  • Lack of travel to, or residence in a Lyme disease endemic area (CDC: Lyme Disease Maps).
  • Following completion of one or more antibiotic course(s) for Lyme disease:
    • Testing should not be used to monitor response to therapy or determine ‘cure.’
  • Due to pressure from patient or patient representatives in the absence of clinical criteria supporting risk for Lyme disease infection.

Experts from the American College of Rheumatology, American Academy of Neurology, and Infectious Diseases Society of America also recommend against routine Lyme testing for people with various non-Lyme conditions such as:

  • Asymptomatic person following a tick bite
  • Amyotrophic lateral sclerosis
  • Relapsing-remitting multiple sclerosis
  • Parkinson’s disease
  • Dementia or cognitive decline
  • New onset seizures
  • Psychiatric illness
  • Developmental or behavioral disorders of children
  • Chronic cardiomyopathy of unknown cause

† list via Wormser et al

See also the following LymeScience pages:

Other misconceptions about Lyme disease diagnosis and testing are discussed below.

Common Misconceptions About Lyme Disease

Table excerpted and reformatted*** from the longer 2013 paper (ref 2 below, which is worth reading):

False negatives

Misconception: “Blood tests are unreliable with many negatives in patients who really have Lyme disease.”

Science: Just as with all antibody-based testing, these are often negative very early before the antibody response develops (<4-6 weeks). They are rarely if ever negative in later disease.

Isolated IgM seropositivity

Misconception: “Patients with many months of symptoms may have only a positive IgM Western blot.”

Science: Because the IgG response develops in 4-6 weeks, patients with symptoms of longer duration than this should be IgG positive; isolated IgM bands in such patients are almost always a false positive.

Seropositivity after treatment

Misconception: “Positive blood tests after treatment mean more treatment is needed.”

Science: After any infection resolves, the immune system continues to produce specific antibodies for an extended period. This is not an indication of persistent infection.

Antibiotics effect on serologic tests

Misconception: “Antibiotics make blood tests negative during treatment”

Science: There is no evidence that this happens and no biologic reason it would.

The clinical diagnosis of Lyme disease

Misconception: “Lyme disease is a clinical diagnosis that should be made based on a list of symptoms.”

Science: No clinical features, except erythema migrans or possibly bilateral facial nerve palsy—in the appropriate context—provide sufficient specificity or positive predictive value. Laboratory confirmation is essential except with erythema migrans.

Persisting fatigue & cognitive symptoms in isolation as evidence of brain infection

Misconception: “Patients with fatigue and memory difficulties have Borrelia burgdorferi infection of the brain.”

Science: These symptoms are not specific for B. burgdorferi infection and only rarely are evidence of a brain disorder.

Severity of Lyme disease

Misconception: “B. burgdorferi infection is potentially lethal.”

Science: Although Lyme disease can cause heart or brain abnormalities, there have been remarkably few—if any—deaths attributable to this infection.

LymeScience note: After this paper was published, CDC published[3] three case studies of deaths associated with Lyme carditis, though two patients had preexisting heart conditions. While it’s not entirely clear if the infection caused the deaths, CDC still reiterates, “Prompt recognition and early, appropriate therapy for Lyme disease is essential.”

Prolonged treatment

Misconception: “If, following treatment, symptoms persist, or serologic testing remains positive, additional treatment is required.”

Science: Multiple well-performed studies demonstrate that recommended treatment courses cure this infection. Retreatment is necessary occasionally, but not frequently.

Symptomatic improvement on antibiotics as validation of the diagnosis

Misconception: “Rapid symptomatic improvement on treatment proves the diagnosis despite negative blood tests.”

Science: Non-microbicidal effects of antibiotics may result in symptomatic improvement. In controlled trials, 1 patient in 3 improved in response to placebo.

Bottom Line

There is substantial evidence supporting the accuracy of FDA-cleared tests once antibodies build up in the body (4-6 weeks post-infection).

The CDC concurs:


You may have heard that the blood test for Lyme disease is correctly positive only 65% of the time or less. This is misleading information. As with serologic tests for other infectious diseases, the accuracy of the test depends upon the stage of disease. During the first few weeks of infection, such as when a patient has an erythema migrans rash, the test is expected to be negative.

Several weeks after infection, currently available ELISA, EIA and IFA tests and two-tier testing have very good sensitivity.

It is possible for someone who was infected with Lyme disease to test negative because:

  1. Some people who receive antibiotics (e.g., doxycycline) early in disease (within the first few weeks after tick bite) may not develop antibodies or may only develop them at levels too low to be detected by the test.
  2. Antibodies against Lyme disease bacteria usually take a few weeks to develop, so tests performed before this time may be negative even if the person is infected. In this case, if the person is retested a few weeks later, they should have a positive test if they have Lyme disease. It is not until 4 to 6 weeks have passed that the test is likely to be positive. This does not mean that the test is bad, only that it needs to be used correctly. [7]

** 99.4% sensitive (95% confidence interval: 95.7–99.9) and 99.3% (95% confidence interval: 98.5-99.7%) specific.

*** LymeScience reformatted the table and added punctuation, emphasis, a note, and changed the word “evidence” to “science”. Excerpted for educational and commentary purposes.

Resources

1. Choosing Wisely: American College of Rheumatology

2. Halperin JJ, Baker P, Wormser GP. Common misconceptions about Lyme disease. Am J Med. 2013 Mar;126(3):264.e1-7.

3. CDC: Three Sudden Cardiac Deaths Associated with Lyme Carditis — United States, November 2012–July 2013

4. CDC: Lyme disease: Diagnosis and Testing

5. CDC: Lyme disease: Laboratory tests that are not recommended

6. CDC scientist Barbara J.B. Johnson, PhD: Book chapter of “Lyme disease: An Evidence-Based Approach”: Laboratory Diagnostic Testing for Borrelia burgdorferi Infection

7. CDC: “I have heard that the diagnostic tests that CDC recommends are not very accurate. Can I be treated based on my symptoms or do I need to use a different test?” Lyme FAQ.

8. Waddell LA, et al. The Accuracy of Diagnostic Tests for Lyme Disease in Humans, A Systematic Review and Meta-Analysis of North American Research. PLoS ONE. 2016;11(12):e0168613.

9. CDC: Notice to Readers: Caution Regarding Testing for Lyme Disease

10. Quackwatch: Some Notes on Nonstandard Lyme Disease Tests

11. Science-Based Medicine: Lemons and Lyme: Bogus tests and dangerous treatments of the Lyme-literati

12. American Lyme Disease Foundation: Antibody-Based Diagnostic Tests for Lyme Disease

13. Botman E, et al. Diagnostic behaviour of general practitioners when suspecting Lyme disease: a database study from 2010-2015. BMC Fam Pract. 2018;19(1):43.

14. Article about “ELISpot” Lyme tests: New test has no added value in Lyme disease of the central nervous system

15. Duerden BI. Unorthodox and unvalidated laboratory tests in the diagnosis of Lyme borreliosis and in relation to medically unexplained symptoms. Department of Health, London, UK, 2006.

16. CDC Q and A: Epidemiology and Clinical Features of Lyme Disease

17. Choosing Wisely: Lyme Disease

18. Gregson D, et al. Lyme disease: How reliable are serologic results? CMAJ. 2015;187(16):1193-4.

19. Marques AR. Laboratory diagnosis of Lyme disease: advances and challenges. Infect Dis Clin North Am. 2015;29(2):295-307.

20. RIVM (Netherlands): Lab tests alone not conclusive for diagnosis of Lyme disease

21. Eldin C, et al. Review of European and American guidelines for the diagnosis of Lyme borreliosis. Med Mal Infect. 2018;

22. Dessau RB, et al. To test or not to test? Laboratory support for the diagnosis of Lyme borreliosis: a position paper of ESGBOR, the ESCMID study group for Lyme borreliosis. Clin Microbiol Infect. 2018;24(2):118-124.

23. Science-Based Medicine: Experts slam CAM lab tests, call for better regulation

24. Dessau RB, et al. The lymphocyte transformation test for the diagnosis of Lyme borreliosis has currently not been shown to be clinically useful. Clin Microbiol Infect. 2014;20(10):O786-7.

25. Lyme Disease Testing: A Regulatory ‘Wild West’

26. Aguero-rosenfeld ME, Wormser GP. Lyme disease: diagnostic issues and controversies. Expert Rev Mol Diagn. 2015;15(1):1-4.

27. A Patient-centered Guide to Lyme Disease Testing

28. Peiffer-smadja N, et al. The French Society of Internal Medicine’s Top-5 List of Recommendations: a National Web-Based Survey. J Gen Intern Med. 2019;

29. Raffetin A, et al. Unconventional diagnostic tests for Lyme borreliosis: a systematic review. Clin Microbiol Infect. 2019;

30. Moore A, et al. Current Guidelines, Common Clinical Pitfalls, and Future Directions for Laboratory Diagnosis of Lyme Disease, United States. Emerging Infect Dis. 2016;22(7)

31. Mead P, et al. Updated CDC Recommendation for Serologic Diagnosis of Lyme Disease. MMWR Morb Mortal Wkly Rep 2019;68:703.

32. Marques AR. Revisiting the Lyme Disease Serodiagnostic Algorithm: the Momentum Gathers. J Clin Microbiol. 2018;56(8)

33. Debiasi RL. A concise critical analysis of serologic testing for the diagnosis of lyme disease. Curr Infect Dis Rep. 2014;16(12):450.

34. European Centre for Disease Prevention and Control. A systematic literature review on the diagnostic accuracy of serological tests for Lyme borreliosis. Stockholm: ECDC; 2016.

35. Van gorkom T, et al. Prospective comparison of two enzyme-linked immunosorbent spot assays for the diagnosis of Lyme neuroborreliosis. [ELISpot, LymeSpot] Clin Exp Immunol. 2019;

36. Theel ES, et al. Limitations and Confusing Aspects of Diagnostic Testing for Neurologic Lyme Disease in the United States. J Clin Microbiol. 2019;57(1)

37. John TM, Taege AJ. Appropriate laboratory testing in Lyme disease. Cleve Clin J Med. 2019;86(11):751-759.

38. Ramsey AH, et al. Appropriateness of Lyme disease serologic testing. Ann Fam Med. 2004.

39. Infectious Diseases Society of America, American Academy of Neurology, and American College of Rheumatology: 2020 guidelines for the prevention, diagnosis, and treatment of Lyme disease.

40. Public Health Wales Observatory: Is there any evidence that testing for Lyme disease using the IGENEX or ARMINLABS facilities is superior to what is available in the UK?

41. Association of Public Health Laboratories: Suggested Reporting Language, Interpretation and Guidance Regarding Lyme Disease Serologic Test Results

42. Jones SL, et al. Laboratory tests commonly used in complementary and alternative medicine: a review of the evidence. Ann Clin Biochem. 2019.

43. Marques AR, et al. Comparison of Lyme Disease in the United States and Europe. Emerging Infectious Diseases. 2021.

44. Andany N, et al. A 35-year-old man with a positive Lyme test result from a private laboratory. CMAJ. 2015.

45. Morshed M, et al. Epidemiology of Lyme disease and pitfalls in diagnostics: What practitioners need to know. BCMJ. 2022.

Studies on inappropriate testing

Al-Sharif B, Hall MC. Lyme disease testing in children in an endemic area. WMJ. 2011.

Vreugdenhil TM, et al. Serological testing for Lyme Borreliosis in general practice: A qualitative study among Dutch general practitioners. Eur J Gen Pract. 2020.

Barclay SS, et al. Misdiagnosis of late-onset Lyme arthritis by inappropriate use of Borrelia burgdorferi immunoblot testing with synovial fluid. Clin Vaccine Immunol. 2012.

Ramsey AH, et al. Appropriateness of Lyme disease serologic testing. Ann Fam Med. 2004

Updated June 17, 2022