Lyme disease is a bacterial infection that occurs when a person is bitten by a tick infected with the Borrelia bacteria. The infection typically begins with flu-like symptoms, but can progress to affect various areas of the body including organs, tissues, and the nervous system. When a person is treated early for Lyme disease, their recovery chances are high. However, Lyme disease isn’t always diagnosed or caught early, which causes many people to suffer from long-term health consequences.
Various tests can be used to help diagnose Lyme disease. Typically, tests check the blood for the presence of a current infection or evidence that someone was infected at some point prior to the test. One such test that can potentially diagnose Lyme disease is the CD57 test. But what is the CD57 test used for, exactly?
What is the CD57 test?
The CD57 test is a type of blood test that can be used to help diagnose Lyme disease. It can also be used to monitor Lyme treatment to see how well it is working and if other avenues need to be explored to help the patient recover.
The test itself looks for the CD57 lymphocyte, which is a type of white blood cell that is part of the immune system. Lymphocytes are typically B cells, which create antibodies, and T cells, which find and kill specific types of pathogens. In a person with Lyme disease, the level of CD57 lymphocytes can be skewed; this helps to determine an infection in someone who is exhibiting symptoms of the disease.
The test itself uses CD markers. CD, or cluster designation, is a type of glycoprotein that can act as an identifier by sitting on the surface of a cell. Each CD is given its own number to distinguish it from the rest. CD57 is used as a marker for Lyme disease because these cells are typically low in people who have the infection.
A CD57 test is often used alongside other types of Lyme disease tests such as the Western Blot test, because other conditions can cause CD57 levels to be abnormal. Further, not all people with Lyme disease will have a changed CD57 count, and thus, other testing should be used to confirm a diagnosis.
How long does a CD57 test take?
The CD57 test is a simple blood test, so the process of getting it done is simple and easy. A needle is used to draw blood from a vein in the arm, just like any regular blood test. The results are then sent to a lab for analysis. Typically, it may take anywhere from one to three days’ time for results to be returned.
The time period in which a CD57 test can be used to determine if a person has Lyme disease varies from person to person, because the immune system must have taken action against Lyme disease for this marker to be used.
What should your CD57 be?
Lymphocytes and other cells all have typical markers they should meet to be in the normal range. In terms of CD57 in a healthy individual, results can range from anywhere between 60 to 360 uL. This likely means that if you get a CD57 test to check for Lyme disease and your results fall within that range, you may not have Lyme disease, or your body may not have yet responded enough to cause low counts of CD57 and indicate you have Lyme disease.
As mentioned above, not all patients with Lyme disease will present with low counts of CD57, so if you think you have Lyme but your test comes back normal, you should still continue with other testing methods to be sure.

What does it mean to have a low CD57 count?
A low CD57 count can indicate Lyme disease, but it typically only occurs when someone has a longstanding active infection. Typically, a person will likely have had chronic Lyme for over a year if their CD57 count is low.
What does a high CD57 count mean?
CD57 levels in chronic Lyme patients can help determine the progression of the infection. As mentioned above, a low count likely means that an active infection is present. The opposite can be true for a high count – if a person with chronic Lyme disease has a high CD57 test result, their levels may indicate that they are going into remission or are already in remission from symptoms and other health consequences.
The CD57 test is a useful tool when diagnosing active long-term infections of Lyme disease. However, if it is being used to diagnose suspected Lyme cases that have only been active for a short time, it should only be a supplemental testing resource because of its limitations in detecting new infection.
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