Your body produces white blood cells (leukocytes), which help fight bacterial infections, viruses and fungi. If your child has too few or too many white blood cells, in general, here's what it means:

  • Low white blood cell count (leukopenia) means having too few leukocytes circulating in the blood. A long-term low white blood cell count increases the risk of infections and may be caused by a number of different diseases and conditions.
  • High white blood cell count (leukocytosis) means having too many leukocytes circulating in the blood, usually from having an infection. A number of different diseases and conditions may cause a long-term high white blood cell count.

There are several types of white blood cells, each with a different disease-fighting activity. The main types are:

  • Neutrophils
  • Lymphocytes
  • Monocytes
  • Eosinophils
  • Basophils

White blood cells disorders involving a specific type of white blood cell include:

  • Neutropenia. Neutropenia (noo-troe-PEE-nee-uh) is a low number of neutrophils, a type of white blood cell that fights infections of fungi and bacteria. Neutropenia can be caused by cancer or by diseases, disorders or infections that damage bone marrow. In addition, certain medications and other diseases or conditions can cause neutropenia.
  • Lymphocytopenia. Lymphocytopenia (lim-foe-sie-toe-PEE-nee-uh) is a decrease in lymphocytes, the type of white blood cell that, among other tasks, protects your body from viral infections. Lymphocytopenia can result from an inherited syndrome, be associated with certain diseases, or be a side effect from medications or other treatments.
  • Monocyte disorders. Monocytes help get rid of dead or damaged tissue and regulate your body's immune response. Infections, cancer, autoimmune diseases and other conditions can cause an increased number of monocytes. A decreased number can be the result of toxins, chemotherapy and other causes.
  • Eosinophilia. Eosinophilia (e-o-sin-o-FIL-e-uh) is a higher than normal number of eosinophil cells, a type of disease-fighting white blood cell. Eosinophilia can be caused by a variety of conditions and disorders, most commonly by an allergic reaction or a parasitic infection.
  • Basophilic disorders. Basophils account for only a small number of white blood cells, but they have a role in wound healing, infection and allergic reactions. A decreased number of basophils can result from high thyroid hormone levels, allergic reactions or infections. An increased number can be caused by certain types of blood cancer, low thyroid hormone levels or other disorders.
  • Expertise and team approach. Your multispecialty team of experts may include pediatric hematologists and pediatric oncologists, as well as other pediatric experts in immunodeficiencies and infectious diseases who work together to provide exceptional care for children and support for families.
  • Experience. Pediatric experts at Mayo Clinic treat more than 370 patients each year with pediatric white blood cell disorders.
  • Newest technology. At Mayo Clinic, your doctor will have access to specialized lab tests and may work with immunologists and infectious disease experts to find the best treatment approach. The Cellular and Molecular Immunology Laboratory, which is part of the Primary Immunodeficiency Center at Mayo Clinic, provides the most modern and cutting-edge testing to identify underlying causes of many white blood cell disorders.
  • Research to improve treatment. Mayo Clinic experts conduct and participate in the latest research on pediatric white blood cell disorders. For example, Mayo Clinic participates in the Severe Chronic Neutropenia International Registry, a global database of treatment outcomes for people with severe chronic neutropenia to aid research and improve treatment.

At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.

Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.

Our patients tell us that the quality of their interactions, our attention to detail and the efficiency of their visits mean health care — and trusted answers — like they've never experienced.

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To diagnose the condition, your child may need the following:

  • Blood tests. If your child's white blood cell count is abnormal, a Mayo Clinic pediatric hematologist will work closely with lab specialists and others to determine the type of white blood cell disorder and the cause.
  • Bone marrow biopsy. Doctors insert a thin needle into the bone to collect a tissue sample and then examine the cells under a microscope.
  • Additional tests. More tests, such as imaging tests, may be needed for proper diagnosis. In tests that involve radiation, specialists carefully monitor doses to avoid the risk of radiation overexposure.

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

Doctors in pediatric hematology and oncology and other pediatric experts in immunodeficiencies and infectious diseases treat pediatric white blood cell disorders at Mayo Clinic's campus in Rochester, Minnesota. Mayo Eugenio Litta Children's Hospital is child-friendly, providing comfortable consultation rooms, imaging areas and inpatient care.

For appointments or more information, call Mayo Clinic Children's Center, 855-MAYO-KID (855-629-6543) toll-free, 7 a.m. to 6 p.m. Central time, Monday through Friday, or use an online appointment form below.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

Jul. 09, 2014