Normal White Blood Cell (WBC) Count

If you have had your blood tested, you may have seen the letters "WBC" among the results. This is your white blood cell (WBC) count. This test is among several that can help your healthcare provider figure out if something is going on inside of your body. It can also help people with chronic illnesses manage their condition and/or monitor their response to treatment.

Read on to learn more about the WBC count, what the range of values means, and why your healthcare provider might order the test.

white blood cell count ranges

Verywell/Nez Riaz

Purpose of the Test

White blood cells are a group of blood cells that fight infection and inflammation in the body. They also protect your body from damage due to toxins (like air pollution) and aid wound healing and tissue repair.

White blood cells are produced in the bone marrow and are an essential part of your immune system. Although they make up less than 1% of your total blood cells, they play a vital role in keeping you healthy.

A WBC count is a test that involves a simple blood draw. A healthcare practitioner will use a thin needle to collect blood from one of your veins, usually in your arm. You can generally get the test results back from the lab in a few days.

Your healthcare provider might order a WBC count if you have any of the following symptoms:

A WBC count measures the total number of all white blood cells in your blood. There are five different types:

  • Neutrophils: These cells help fight bacteria and fungal infections. They usually make up 50% to 75% of all your white blood cells.
  • Lymphocytes: These cells help fight infections and produce immune proteins called antibodies. and attack tumors. Lymphocytes are found in both your blood and lymph tissues.
  • Monocytes: These cells help damaged or dead cells from the body. They also travel into tissues like the lungs and liver and become another type of cell that help eases inflammation.
  • Eosinophils: These cells fight infections caused by parasites. They also respond to allergic reactions and inflammation.
  • Basophils: These cells release a chemical called histamine during an allergic response. This triggers symptoms like a runny nose or watery eyes.

If you see these five cell types on your results along with numeric values, it is because your healthcare provider ordered a WBC differential test. The "diff" test looks at each of the cell types to figure out what's going on in the body based on which values are either high or low. Doing so helps narrow the possible causes.

WBC counts are often part of a more comprehensive test called a complete blood cell (CBC) count. The CBC count looks not only at white blood cells but also at red blood cells (that transport oxygen throughout the body) and platelets (that are responsible for blood clotting).

A CBC count is a common test used to evaluate your overall health and detect a wide range of illnesses, including anemia, infections, and disease like leukemia.

Normal Reference Range of Values

No hard-and-fast number defines what a "normal" WBC count is. Instead, the results are reported in relation to the normal expected range of values within a population. Anything below this range is low, and anything above this range is considered high.

A low or high WBC count doesn't mean the same for all people, mainly if the values are borderline. This is because a "normal" WBC count can vary from one person to the next based on age, sex, race, smoking status, and other factors. WBC counts can also fluctuate throughout the day.

Labs can also differ in defining a high or a low WBC count. So, it is possible to have a normal WBC at one lab and find that you have a low or high WBC count at another. (This is why people who require ongoing blood tests are advised to use the same lab provider for all tests.)

WBC counts are measured by the number of white blood cells per cubic millimeter of blood (cells/mm3). Here is an example of how a lab might define the expected range of values for a WBC count:

 Example of WBC Count Reference Ranges
Low Under 4,000 cells/mm3
Normal reference range 4,500 to 10,000 cells/mm3
High Over 10,000 cells/mm3

Interpreting Results

The WBC count isn't specific enough to diagnose any particular disease. Abnormal values are simply an indication that something may be wrong and what the possible causes may be.

If your WBC count is high, you have what is called leukocytosis. Among some of the possible causes of leukocytosis are:

  • A bacterial, fungal, or parasitic infection
  • Inflammatory conditions
  • Burns
  • Steroid use
  • Cigarette smoking
  • Pregnancy
  • Leukemia

If your WBC count is low, you are said to have leukopenia. Among some of the possible causes of leukopenia are:

  • A blood or bone marrow disorder
  • Autoimmune disorders
  • Medication side effects
  • Chemotherapy or radiation therapy
  • A viral infection

Abnormal WBC Count Due to Medications

Many prescription and over-the-counter drugs can cause an abnormal WBC count. It is essential always to review your medication history with your healthcare provider.

Certain drugs can cause your WBC count to drop below the normal range of values. These include:

Some medicines can raise your WBC count. Some of the more common include:

Follow-Up Tests

If your WBC count is abnormal, your healthcare provider may order additional tests depending on your symptoms and medical history. These may include tests to see if you have:

  • An infection: Your healthcare provider may order a urinalysis, for example, if they think you have a urinary tract infection. If they believe you have a viral infection, they might contain a polymerase chain reaction (PCR) test to identify the suspected virus.
  • An inflammation problem: Your healthcare provider may order a C-reactive protein (CRP) test. CRP is a type of protein that increases if you have inflammation anywhere in the body.
  • An autoimmune disorder: Your healthcare provider may order an antinuclear antibody test (ANA) to detect if there are immune proteins, called autoantibodies, in your blood.
  • An allergy: Your healthcare provider may order a skin prick test or food allergy test to see what you may be allergic to.
  • Leukemia: Your healthcare provider may order a bone marrow biopsy or a microscopic evaluation of your blood using a tool called flow cytometry.

Summary

White blood cells help fight infection and inflammation. A white blood cell (WBC) count measures the number of white blood cells in a sample of blood. Many conditions, including infections, medications, inflammatory diseases, and blood or bone marrow disorders, can cause an abnormal WBC count.

The WBC count is measured in a reference range of values by the number of blood cells in a cubic millimeter of blood. Test results can vary by the lab you use and how it defines a low, normal, or high range.

A WBC count isn't specific enough to diagnose a particular disease or condition. Still, the test can provide valuable clues as to what is causing your symptoms.

A Word From Verywell

It's important to discuss your WBC count results—and any other test you undergo—with your doctor to understand what they mean. Doing so allows you to make informed choices about your health.

It is also important not to jump to conclusions if you see a "high" or "low" notation on your WBC count results. It is only by comparing the test results to different blood test values that a healthcare provider can start narrowing down the possible causes.

Was this page helpful?
14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. King W, Toler K, Woodell-May J. Role of white blood cells in blood- and bone marrow-based autologous therapies. Biomed Res Int. 2018;2018:6510842. doi:10.1155/2018/6510842

  2. Kabat GC, Kim MY, Manson JE. White blood cell count and total and cause-specific mortality in the Women's Health Initiative. Am J Epidemiol. 2017 Jul 1;186(1):63–72. doi:10.1093/aje/kww226

  3. MedlinePlus. White blood count (WBC).

  4. National Cancer Institute. Dictionary of cancer terms.

  5. MedlinePlus. Complete blood count (CBC).

  6. Coates S, Wang D, Pierscionek T, et al. Time- and race-specific haematological reference intervals for healthy volunteer trials: a retrospective analysis of pooled data from multiple phase I trials. Front Pharmacol. 2020 Mar 13;11:314. doi:10.3389/fphar.2020.00314

  7. Riley LK, Rupert J. Evaluation of patients with leukocytosis. Am Fam Physician. 2015;92(11):1004-11.

  8. Newburger PE, Dale DC. Evaluation and management of patients with isolated neutropenia. Semin Hematol. 2013;50(3):198-206. doi:10.1053/j.seminhematol.2013.06.010

  9. Moore DC. Drug-induced neutropenia: a focus on rituximab-induced late-onset neutropenia. P T. 2016 Dec;41(12):765–8.

  10. Van Seventer JM, Hochberg NS. Principles of infectious diseases: transmission, diagnosis, prevention, and controlInt Encycloped Pub Health. 2017;22-39. doi:10.1016/B978-0-12-803678-5.00516-6

  11. MedlinePlus. C-reactive protein (CRP) test.

  12. American College of Rheumatology. Antinuclear antibodies (ANA).

  13. American College of Allergy, Asthma & Immunology. Allergy testing,

  14. Davis AS, Viera AJ, Mead MD. Leukemia: an overview for primary careAm Fam Physician. 2014;89(9):731-8.