by Stephanie Eckelkamp
Posted 3/8/23

The Borrelia burgdorferi bacterium that causes Lyme disease is a master at laying low, burrowing into your tissues (potentially laying dormant for a period before symptoms arise), and blending in with the numerous other microbes present in your body at any given time. It doesn’t need to be present in high concentrations to cause illness, either. All of which makes testing tricky.

Common diagnostic tests such as the ELISA and Western Blot (meant to detect antibodies to borrelia and most useful in acute cases of Lyme), PCR tests (meant to detect borrelia DNA), and even blood and tissue cultures are notoriously bad at providing accurate results, especially for chronic Lyme disease. More than 50% of people with Lyme-related symptoms won’t meet the criteria for diagnosis.

These are a few reasons some Lyme practitioners recommend the CD57 test — a blood marker for a particular type of white blood cell. Supposedly, this test can help confirm a Lyme disease diagnosis and be used to monitor how efficiently a treatment is working. Below, we discuss the actual utility of this test. Plus, why you may not need a positive test result of any kind to start healing from Lyme (and the other stealth microbes that could be driving your illness).

What Is a CD57 Test?

CD57 is a cell-surface marker that’s present on a certain subset of natural killer (NK) cells — a type of white blood cell that helps wipe out cells infected with intracellular microbes. A CD57 test measures the levels of these CD57 NK cells in the blood.

The rationale behind testing: Research from 2001 by hematologist Raphael Stricker, MD, found that patients with chronic Lyme disease were more likely to have significantly decreased CD57 NK cell counts than control groups, and their CD57 levels came back up to a normal range after completing antibiotic therapy. This, some have argued, makes the CD57 test a useful tool for confirming a Lyme diagnosis (particularly when other tests are inconclusive) and for monitoring the effectiveness of treatment protocols (because the idea goes, if your CD57 levels come back up to a normal range after treatment, then that treatment is working).

What Do Studies and Experts Say about CD57?

While CD57 may sound good in theory, this test is far from a magic bullet. “I don’t see it as a reliable marker for Lyme,” says Dr. Bill Rawls, MD, medical director of RawlsMD and Vital Plan. “There was a suggestion that low levels of this particular natural killer cell might indicate an active infection of borrelia, but the problem is that the test is not specific to borrelia.”

Low levels — often defined as below 60 — could be an indicator of another chronic infectious disease or health condition. As physician Marty Ross, MD, puts it: “It can be a suggestion of active Lyme, but it doesn’t prove that Lyme disease is a cause of that low CD57.”

Case in point: In a 2020 research review on unconventional Lyme disease testing, the authors noted that low CD57 levels were also found in patients with autoimmune diseases, cancers, and infections, and no study to date has demonstrated the test’s sensitivity or specificity for Lyme disease.

Another study from 2009 found no significant difference between the CD57 levels of normal controls and patients with Lyme disease. This tracks with Dr. Rawls’ own experience. “I got this test when I was at my peak of misery with chronic Lyme, and my results were only borderline high, so it was not valuable at all,” he says.

Additionally, in a video on Dr. Ross’ website, he emphasizes that he doesn’t find the test helpful in monitoring the success of a person’s treatment either — “because [for] many people, when we treat their Lyme, the CD57 does not increase at the end.”

There are also no studies to indicate whether this lack of increase after treatment means a patient will have worse outcomes or be more likely to relapse. So it’s unclear what these results are even telling us. As opposed to relying on a questionable test to tell you you’re improving? “The best indicator that you’re getting well is when your symptoms resolve,” says Dr. Rawls. “If your symptoms are resolving, it means that your cells are recovering from the illness.”

Keep in mind, Lyme disease is a clinical diagnosis based on your medical history, symptoms, and exposure or proximity to ticks — so a positive test may not always be necessary to identify Lyme and move forward with treatment. If additional confirmation is needed, there are more reliable tests than the standard Western blot you’d get from your primary care physician’s office. These tests, from labs such as IGeneX, Galaxy Diagnostics, and Vibrant Wellness, can reveal which species of borrelia and coinfections you may have been exposed to, which could help you better customize your treatment protocol. (Spoiler: there are a lot more possibilities out there than just Borrelia burgdorferi),

Don’t Assume You Need Testing to Start Healing

While Dr. Rawls does not find any utility in the CD57 test, some physicians may still use it if they want one more laboratory clue. But again, something else besides Lyme could be causing that CD57 test to be low. Additionally, Dr. Rawls doesn’t believe you need to wait for a positive CD57 or any type of Lyme test before taking steps to heal. Here’s why:

It’s Rarely Just One Microbe

It’s probably not just Lyme disease driving your symptoms — so testing may not always produce helpful results. As humans, we accumulate a lot of microbes in our tissues over time, which can lie dormant in our bodies until a significant physical or mental stressor lowers our immune defenses and prompts their reactivation. Symptoms you assume are solely Lyme-related could be the result of the tick-borne disease or the many viruses and bacteria you’ve accumulated over your lifetime.

Therefore, it might be completely unreasonable to think you could test for, detect, and then successfully treat the “one” thing driving your illness. “I’ve researched probably a hundred different microbes that can cause Lyme disease-like symptoms,” says Dr. Rawls. “If you look at chronic Lyme disease as more of an activation of all these things you’ve accumulated, testing just doesn’t do very much.” If borrelia was causing these symptoms (in exclusion of everything else) and we had a specific treatment for it, testing would be valuable — but that’s not how it is, he says.

You Can Heal Without A Positive Test

For many chronic illnesses (Lyme, fibromyalgia, ME/CFS, long COVID), the road to healing looks similar — and you don’t need a positive test to get started. There’s never a single pill or therapy that completely eradicates a chronic illness, especially if your illness results from multiple microbes working together. The focus, instead, should be on optimizing cellular health. “If cells are healthy and cellular functions are coordinated, the body is going to self-regulate,” he says.

The best part: You don’t need a positive test result to boost cellular functioning. Dr. Rawls recommends taking strategic steps to optimize your diet, stress levels, sleep, toxin exposure, and physical activity and experimenting with a comprehensive herbal therapy protocol to address Lyme and a spectrum of coinfections to lower cellular stress and support healing.

Bottom Line

Lyme disease testing, in general, is unreliable, and the CD57 test is no different — it’s not specific to Lyme disease, so it’s not a foolproof way to confirm a Lyme diagnosis. Also, there’s no good data to confirm its efficacy in monitoring the progress of Lyme treatment. Rather than relying solely on testing, it may be more worthwhile to place more emphasis on optimizing cellular health from multiple angles, suggests Dr. Rawls.

Dr. Rawls is a physician who overcame Lyme disease through natural herbal therapy. You can learn more about Lyme disease in Dr. Rawls’ new best selling book, Unlocking Lyme.

You can also learn about Dr. Rawls’ personal journey in overcoming Lyme disease and fibromyalgia in his popular blog post, My Chronic Lyme Journey.

1. CD-57 Test? Rarely. Treat Lyme website.
2. IGeneX Legacy Tests. IGeneX website.
3. Marques A, Brown MR, Fleisher TA. Natural killer cell counts are not different between patients with post-Lyme disease syndrome and controls. Clin Vaccine Immunol. 2009;16(8):1249-1250. doi:10.1128/CVI.00167-09
4. Raffetin A, Saunier A, Bouiller K, et al. Unconventional diagnostic tests for Lyme borreliosis: a systematic review. Clin Microbiol Infect. 2020;26(1):51-59. doi:10.1016/j.cmi.2019.06.033
5. Stricker RB, Winger EE. Decreased CD57 lymphocyte subset in patients with chronic Lyme disease. Immunol Lett. 2001;76(1):43-48. doi:10.1016/s0165-2478(00)00316-3