What Do Low Lymph Levels Mean in a Complete Blood Count?


Your lymphocyte levels (often simply called lymph levels) are checked every year when you go to your yearly physical. As part of the routine physical, your doctor will order a complete blood count (CBC) test, which checks for various different levels to make sure your body is working properly. If your lymph levels are too low or too high, it could be a sign of illness or disease. Read on to learn about lymphocytes and how they work, what low levels mean, and what you should do if levels are low.

What Are Lymphocytes?

Made in the bone marrow, lymphocytes are a type of white blood cell that aids the immune system in keeping us free from illness and disease. When they’re working properly, lymphocytes can defend the body against viruses, disease, bacteria and other conditions. There are several different types of lymphocytes, known as B and T cells, as well as subsets within each type. 

What Do Lymphocytes Do?

There are three main types of lymphocytes: B,  T and NK cells.Generally speaking, the job of each B cell is to make antibodies to fight antigens (which is another term for a foreign substance). T cells control the immune response and also fight cancer cells. There are subsets of each:

  • Memory B cells live in the body for years and have a “memory” of previously found antigens, allowing them to fight disease faster.
  • Regulatory B cells are small in number, but have a very important job of fighting inflammation.
  • Killer T cells look throughout the body for germ-infected cells, which they kill when found.
  • Helper T cells work with other lymphocytes to help protect the immune system.
  • Regulatory T cells work to prevent inflammation and autoimmune problems, but can also interfere with the immune system, allowing certain antigens to have access to cells.
  • Memory T cells, like memory B cells, remember previous antigens and work quickly to protect the body.

There is also another type of lymphocyte known as Natural Killer (NK) cells. Their job is to react quickly and purge foreign substances in the body.

What Are Normal Lymph Levels?

Normal lymphocyte levels can vary based on age, race, gender and state of health. Generally speaking, however, normal lymph ranges fall between 1,000 and 4,800 lymphocytes in 1 microliter. This varies with children, and normal levels for children are between 3,000 and 9,500 lymphocytes in 1 µL of blood. If you have lymph levels that are above or below these parameters, it may be indicative of disease. 

What Might Low Lymph Levels Indicate?

Lymph levels that are lower than normal may be a temporary condition and may not even be a cause for concern. If you’ve recently had a cold or virus, exercised vigorously before your blood test, or are suffering from stress or inflammation, it may cause your lymph levels to be low. Your doctor will likely order further workup before giving you a clean bill of health.

Another cause of low lymph levels could be lymphocytopenia, which is simply another term for low lymph count not due to a temporary condition. Lymphocytopenia is usually a marker of a deeper issue, such as inherited diseases like ataxia-telangiectasia, autoimmune disease, multiple sclerosis or HIV/AIDS. More tests are needed to determine the root cause. 

What Might High Lymph Levels Indicate?

Like low levels, a high lymph count may be due to a temporary condition, such as inflammation or a virus. High levels can also indicate lymphocytosis, which is associated with autoimmune diseases such as inflammatory bowel disease (IBD), which is a blanket term for the combination of ulcerative colitis (UC) and Crohn’s disease. Like with a low count, it’s likely your doctor would want to run more tests. 

What Is a B and T Cell Screen?

If you have a low or high lymph count, your doctor may want to look at B and T cells individually to try to diagnose what may be causing the problem. A B and T cell screen is simply another blood test ordered by your doctor that takes a look at individual cells. High T cell counts may indicate conditions such as sexually transmitted diseases (STDs), viral infections, cancer and tuberculosis (TB). High B cell counts can indicate leukemia or multiple myeloma. Low T cells may reveal HIV/AIDS or cancer, and low B cell counts may be indicative of leukemia, AIDS or autoimmune diseases. To pinpoint an exact diagnosis, your physician may also want to take a sample of your bone marrow.