Your white blood cell count, also referred to as WBC count, looks at the quantity of white blood cells present in your blood. These cells, known as leukocytes, work to fight infections. They attack and destroy bacteria, viruses and other organisms that cause infections. Although there are fewer white blood cells than red blood cells, they are larger. Some people have an elevated white blood cell count due to a bacterial infection. 

What Can Be Considered as Elevated White Blood Cell Count?

The exact white blood cell count will vary between laboratories, but there are typically 4,300 to 10,800 cells for each cubic millimeter blood. So the threshold for elevated white blood cell count differs from one medical practice to another. Generally, for adults, a count of over 11,000 leukocytes in one microliter of blood is considered elevated white blood cell level. But this threshold varies in children according to their age and size. 

Elevated White Blood Cell Count, Why?

Why do we have elevated white blood cell count? Here are the  main reasons for a high white blood cell count:

1. Stress

Severe emotional or physical stress may increase your white blood cell count. This includes stress due to anxiety and overexertion. Stress boosts cortisol and other hormone levels within your blood, which may be linked to more white blood cells entering the bloodstream.

2. Infection

The most common cause of a high WBC count is a viral or bacterial infection, but fungal and parasitic infections can also lead to an elevated count. The rise in WBC is due to the immune system's normal response. It triggers your bone marrow to release the stored extra white blood cells, letting them enter the blood and fight the disease. In case of viral infections, the elevated white blood cell count will typically occur during the early stages because your immune system sends white blood cells into your blood to attack the virus.

3. Inflammation

Conditions known for inflammation, like rheumatoid arthritis, may also lead to a rise in your white blood cell count. Other sources of inflammation include injury and tissue damage like surgery, heart attacks, burns, asthma and severe allergies. Besides, COPD (chronic obstructive pulmonary disease) is frequently caused by smoking cigarettes. This, in turn, leads to inflammation of the air passages and lungs.

When inflammation occurs, your body responds by increasing a particular type of chemical message. This message leads to white blood cells stored in bone marrow being released to fight off the inflammation.

4. Bone Marrow Diseases

In serious cases, a high WBC count may be due to a bone marrow disorder.

• Leukemia is one of that kind of diseases. In this case, the bone marrow produces large quantities of abnormal white blood cell and then releases them into your bloodstream.
• Polycythemia vera is another bone marrow disease which may be responsible. It happens because of an abnormal gene, leading to overproduction of red and white blood cells.
• Myelofibrosis is another possible cause and this involves the bone marrow being replaced with scar-like tissue. Then abnormal blood cells may be produced, and if there are inflammations, white blood cells will be increase during initial phase of this disease.

5. Other Causes of Elevated White Blood Cell Count

• Medication reaction: There are also some medications that may increase the number of white blood cells released into your blood. These include drugs to treat cancer, mental health conditions and inflammation.
• Immune system diseases: Crohn's, Grave's and other autoimmune disorders may also lead to elevated white blood cell counts, so your doctor will monitor your condition.
• Exercise: Testing your blood right after exercising will almost always show you have an elevated white blood cell count. The levels will increase proportionally with the duration and intensity of your workout, so you should not be alarmed in these conditions. 

When to Worry

Remember that it is completely normal to experience high white blood cells levels during an infectious illness. Your levels should go back down to normal levels after your infection or illness is under control.

If you haven't recently had any of infections and your blood tests show an elevated white blood cell count, you will need to visit a hematologist. They will review the tests and conduct a thorough check-up to find out why your body is producing so many white blood cells. A specialist will be able to find the cause and determine the ideal treatment.

Note: Your diet also impacts your white blood cell count. To help maintain the proper levels, avoid foods with high levels of salt, sugar, calories or fat. Instead, opt for low glycemic foods rich in antioxidants. Try to have 6 servings of veggies and fruit per day and pick foods that lower inflammation, which should include garlic, herbs, spices, grapes, olive oil, nuts, green or black tea and vinegar.

Watch the following video to find out more reason for elevated white blood cell count, when to worry and how to do with it: