White blood cells help fight infections by attacking bacteria, viruses, and germs that invade the body.
A WBC count can detect hidden infections and undiagnosed medical conditions.
A healthcare provider or lab technician will draw blood to check your WBC count.
A white blood cell (WBC) count is a test that measures the number of white blood cells in your body. This test is often included with a complete blood count (CBC).
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.
WBCs, also called leukocytes, are an important part of the immune system. These cells help fight infections by attacking bacteria, viruses, and germs that invade the body. White blood cells originate in the bone marrow but circulate throughout the bloodstream. There are five major types of white blood cells:
neutrophils
lymphocytes
eosinophils
monocytes
basophils
Having a higher or lower number of WBCs than normal may be an indication of an underlying condition. A WBC count can detect hidden infections within your body and alert doctors to un-diagnosed medical conditions, such as auto-immune diseases, immune deficiencies, and blood disorders. This test also helps doctors monitor the effectiveness of chemotherapy or radiation treatment in people with cancer.
NORMAL RANGE
What is a normal WBC count?
An average normal range is between 3,500 and 10,500 white blood cells per microliter of blood (mcL). Infants are often born with much higher numbers of WBCs, which gradually even out as they age. According to the Mayo Clinic, these are the normal ranges of WBCs per micro-liter of blood by age:
Age White blood cells per mcL of blood
immediately after birth 9,000 to 30,000
1 to 7 days 9,400 to 34,000
8 to 14 days 5,000 to 21,000
15 days to 1 month 5,000 to 20,000
2 to 5 months 5,000 to 15,000
6 months to 1 year 6,000 to 11,000
2 years 5,000 to 12,000
3 to 5 years 4,000 to 12,000
6 to 11 years 3,400 to 10,000
12 to 15 years 3,500 to 9,000
adults 3,500 to 10,500
These normal ranges can vary by lab. Another common measurement for the volume of blood is cubic millimeter, or mm3. A micro-liter and cubic millimeter are the same amount.
The types of cells that make up WBCs usually fall within a normal percentage of your overall white blood cell count.
The normal percentages of the types of WBCs in your overall count are usually in these ranges:
Type of WBC Normal percentage of overall WBC count
neutrophil 45 to 75 percent
lymphocyte 20 to 40 percent
eosinophil less than 7 percent
monocyte 1 to 10 percent
basophil less than 3 percent
Higher or lower numbers of WBCs than normal can be a sign of an underlying condition. Having a higher or lower percentage of a certain type of WBC can also be a sign of an underlying condition.
SYMPTOMS OF AN ABNORMAL COUNT
Symptoms of an abnormal WBC count
The symptoms of a low WBC count include:
body aches
fever
chills
headaches
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 white blood cell count may prompt your doctor to recommend a WBC count. It’s also normal for doctors to order a complete blood count and check your WBC count during an annual physical examination.
PROCEDURE
What to expect from a WBC count
A healthcare provider or lab technician will draw blood to check your WBC count. This blood sample is 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 provider will clean the needle site to kill any germs and then 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.
The healthcare provider slowly inserts a needle into your arm or hand and collects the blood in an attached tube. The provider then removes the elastic band from around your arm and slowly removes the needle. The technician will apply gauze to the needle site to stop the bleeding.
Healthcare providers use a different technique when drawing blood from young children and infants. With them, providers first puncture the skin with a lancet (a pricking needle) and then use a test strip or a small vial to collect the blood. Results are sent to a lab for review.
Having your blood drawn is a simple procedure, and complications are extremely rare. It can be difficult to take blood from people with small veins. The lab technician may be unable to locate a vein, 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 a sharp pain or a stinging sensation.
Rare complications include:
-infection at the needle site
-excessive bleeding
-lightheadedness or fainting
-bleeding underneath the skin (hematoma)
PREPARATION
How to prepare for a WBC count
A WBC count requires no specific preparation. You simply schedule an appointment with your 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.
The drugs that may affect your test results include:
-corticosteroids
-quinidine
-heparin
-Clozapine
-antibiotics
-antihistamines
-diuretics
-anticonvulsants
-sulfonamides
-chemotherapy medication
Prior to having your blood drawn, tell your doctor about all prescription and nonprescription medications that you’re currently taking.
RESULTS
Understanding WBC count test results
Abnormal test results are classified by numbers that 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, symptoms, and medical history.
Leukopenia is the medical term used to describe a low WBC count. A low number can be triggered by:
HIV
autoimmune disorders
bone marrow disorders/damage
lymphoma
severe infections
liver and spleen diseases
lupus
radiation therapy
some medications, such as antibiotics
Leukocytosis is the medical term used to describe a high WBC count. This can be triggered by:
smoking
infections such as tuberculosis
tumors in the bone marrow
leukemia
inflammatory conditions, such as arthritis and bowel disease
stress
exercise
tissue damage
pregnancy
allergies
asthma
some medications, such as corticosteroids
After diagnosing the cause of a high or low WBC count and recommending a treatment plan, your doctor will periodically recheck your white blood cells. If your white blood cell count remains high or low, this can indicate that your condition has worsened. Your doctor may adjust your treatment. If your WBC count shows a normal range, this usually indicates that the treatment is working.
Q&A
Q&A: Increasing your WBC count
Are there any foods I can eat that will help increase my WBC count?
No specific foods or diet is proven through research to increase the production of white blood cells. It’s important to include a good source of protein in your diet, as amino acids found in protein are needed to build WBCs. Vitamins B-12 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.
Medically Reviewed by Deborah Weatherspoon, PhD, RN, CRNA, COI on March 6, 2017 — Written by Valencia Higuera