A healthy white blood cell count is key to a properly functioning immune system. Causes of a low or high white blood cell count include conditions that affect the immune system, infections, and certain medications.
A white blood cell (WBC) count is a test that measures the number of white blood cells in your body. It may also be called a leukocyte test. This test is often included with a complete blood count (CBC), which is commonly used to screen for different conditions that may affect your overall health.
The term “white blood cell count” is also used more generally to refer to the number of white blood cells in your body.
There are several types of white blood cells, and your blood usually contains a percentage of each type. Sometimes, however, your white blood cell count can fall or rise out of the healthy range. This may be due to an underlying condition or infection.
Keep reading to learn the normal white blood cell count range is and what high or low white blood cell counts may mean.
A WBC count is often done as part of a CBC. These tests may be ordered as part of a routine blood test.
White blood cells, also called leukocytes, are an important part of the immune system. They originate in the bone marrow but move throughout the bloodstream. These cells help fight infection by attacking bacteria, viruses, and germs that invade the body.
A white blood cell count can detect hidden infections within your body and alert doctors to undiagnosed medical conditions, such as autoimmune diseases, immune deficiencies, and blood disorders. This test also helps doctors monitor the effectiveness of chemotherapy, radiation treatment, and other therapies in people with cancer.
White blood cell differential
Doctors may also order a white blood cell count differential, which provides a breakdown of your white blood cell count. It separates the count out by the different types of white blood cells and looks to see if they are in the normal range.
There are five major types of white blood cells. They have different roles in protecting your body from infection and dealing with infected cells. These types of white blood cells include:
A normal white blood cell count can indicate that your immune system is functioning as normal. The normal range for a white blood cell count is typically between 4,000 and 11,000/microliters.
Factors like age and sex may determine what a normal range looks like.
According to the Leukemia and Lymphoma Society (LLS), these are the normal white blood cell count ranges for people in the following groups:
|WBC range per μL of blood
|5,000 to 10,000
|4,500 to 11,000
|5,000 to 10,000
Note that pregnant people may have a white blood cell count that differs from these ranges. Newborns and children under two may also have ranges that differ from those listed above.
These normal ranges can also vary by lab. The lab performing your test may include a reference range listed on your report.
Another common measurement for the volume of blood is cubic millimeter, or mm3. A microliter and cubic millimeter equal the same amount.
The types of cells that make up WBCs usually fall within a normal percentage of your overall WBC count.
The normal percentages of the types of WBCs in your overall count are usually in these ranges, according to the LLS:
|Type of WBC
|Normal percentage of overall WBC count
|55% to 70%
|20% to 40%
|1% to 4%
|2% to 8%
|0.5% to 1%
Having a higher or lower percentage of a certain type of white blood cell can also be a sign of an underlying condition.
If your test results are abnormal, it may mean that your numbers are higher or lower than the normal range for your age.
A low or high WBC count can point to a blood disorder or other medical condition. To identify the exact cause of a high or low WBC count, your doctor will take several factors into consideration, such as your list of current medications, any symptoms you have, and your medical history.
Low white blood cell count
Leukopenia is the medical term used to describe a low WBC count. This can be triggered by:
- autoimmune disorders
- bone marrow disorders or damage
- severe infections
- liver and spleen diseases, such as an enlarged spleen
- radiation therapy
- some medications, such as chemotherapy and antibiotics
Sometimes, the term neutropenia is also used to indicate a low blood count. This term actually refers to a low number of neutrophils but because this type of white blood cell makes up 55 to 70 percent of your overall white blood cells, leukopenia is often driven by a low number of neutrophils.
Having neutropenia may put you at an increased risk for infection, illness, and death. This is because you may not have enough white blood cells to protect you from germs and bacteria. If you have this condition, it is important to take precautions such as wearing a mask in public settings to limit your exposure and reduce your risk of infection.
High white blood cell count
Leukocytosis is the medical term used to describe a high WBC count. This can be triggered by:
- infections such as tuberculosis, sepsis, or septic shock
- injury or burn
- a recent vaccination
- some medications, such as corticosteroids, epinephrine, and non-steroidal anti-inflammatory (NSAID) drugs
- tissue damage
- acute hemolysis
- leukemoid reaction
- heart attack
An elevated white blood cell count may also be chronic or long lasting with the following conditions:
- tumors in the bone marrow
- inflammatory conditions, such as arthritis and bowel disease
- vasculitis, or inflammation of the blood vessels
The doctor may run additional tests to determine the cause of your abnormal white blood cell count.
After diagnosing the cause of a high or low WBC count and recommending a treatment plan, your doctor will periodically recheck your WBCs with additional blood tests.
If your WBC count remains high or low, this can indicate that your condition has worsened. Your doctor may use this information to adjust your treatment.
If your WBC count shows a normal range, this usually indicates that the treatment is working.
The symptoms of a low WBC count include:
High WBC counts don’t often cause symptoms, although the underlying conditions causing the high count may cause their own symptoms.
The symptoms of a low WBC count may prompt your doctor to recommend a WBC count. It’s also normal for doctors to order a CBC and check your WBC count during an annual physical exam.
A WBC count requires no specific preparation. You simply schedule an appointment with a doctor or set up an appointment at a local medical laboratory.
Certain medications can interfere with your lab results and either lower or increase your WBC count. Drugs that may affect your test results can include:
- chemotherapy medication
Prior to having your blood drawn, tell your doctor about all prescription and nonprescription medications that you’re currently taking.
A healthcare professional or lab technician needs to draw blood to check your WBC count.
This blood sample is typically taken either from a vein in your arm or a vein on the back of your hand. It only takes a couple of minutes to draw your blood, and you may experience minor discomfort.
The healthcare professional first cleans the site to kill any germs. Then, they will typically tie an elastic band around the upper section of your arm. This elastic band helps the blood fill your vein, making it easier for the blood to be drawn.
They may then insert a needle into your arm or hand to collect the blood in an attached tube. After, they will remove the elastic band from around your arm and remove the needle. Finally, the technician may apply gauze or a bandage to the site to stop the bleeding.
There’s typically a different technique for drawing blood from young children and infants. This may include first puncturing the skin with a lancet (a pricking needle) and then using a test strip or a small vial to collect the blood.
A laboratory typically processes these results. You may receive your results online, over a phone call, or during a follow-up visit.
Having your blood drawn is a simple procedure, and complications are rare.
However, it can be difficult to take blood from people with small veins. The lab technician may be unable to locate a vein the first time, or once the needle is inside the arm or hand, they may have to move the needle around in order to draw blood. This can cause sharp pain or a stinging sensation.
Rare complications of a blood test may include:
Are there any foods I can eat that will help increase my WBC count?Anonymous
No specific foods or diet is proven through research to increase the production of white blood cells.
Vitamins B12 and folate are also needed to produce WBCs, so consider adding a multivitamin and mineral supplement daily. Though not proven, some believe that adding vitamin C, vitamin E, zinc, garlic, selenium, and even spicy foods to your diet can boost the immune system.
If you’re being treated for cancer or other causes of leukocytosis, talk to your doctor before taking any supplements, as they might interfere with treatments.Deborah Weatherspoon, PhD, RN, CRNAAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.