A complete blood count (CBC) is a standard laboratory test that offers a snapshot of the cells circulating in the bloodstream, including red blood cells, platelets, and white blood cells (WBCs). The WBC count is a fundamental metric that reflects the activity of the body’s immune system. These cells, also known as leukocytes, are primarily manufactured in the bone marrow and travel through the blood and lymphatic tissues.
What White Blood Cells Do
White blood cells (leukocytes) identify and neutralize foreign invaders like bacteria, viruses, and parasites. This specialized defense system is composed of five distinct types of leukocytes, each playing a specific role in immunity.
- Neutrophils are the most abundant type, engulfing and destroying bacteria and fungi.
- Lymphocytes target viral infections and generate antibodies for long-term immunity.
- Monocytes migrate into tissues, transforming into macrophages to consume damaged cells and infectious debris.
- Eosinophils combat parasitic infections and play a role in allergic reactions.
- Basophils release histamine and other chemicals that initiate allergic responses, such as inflammation.
Interpreting a Count of 14.7
A total WBC count is reported in thousands of cells per microliter of blood. For most adults, the generally accepted normal range falls between 4.5 and 11.0 thousand cells/µL. A value that exceeds this upper limit, such as 14.7 thousand cells/µL, is defined as an elevated white blood cell count, a condition medically termed leukocytosis. This result indicates a moderate increase, suggesting the body’s defense system is actively responding to a stimulus. While significant enough to confirm an active biological process, 14.7 is often associated with a localized or temporary event rather than a severe, systemic disorder.
Common Causes of Elevated WBCs
The key to understanding a WBC count of 14.7 lies not only in the total number but also in the differential count, which reports the percentage and absolute number of each of the five cell types. This breakdown allows health providers to narrow down the potential cause of the elevation. A rise predominantly in neutrophils, for example, points toward a different cause than an increase in lymphocytes or eosinophils.
Infection and Inflammation
The most frequent reason for a moderate elevation is the body’s reaction to infection or inflammation. Bacterial infections commonly trigger a surge in neutrophils (neutrophilia) as these cells rush to the site of invasion. Conversely, many viral illnesses, such as the flu or mononucleosis, are more likely to result in an increase in lymphocytes (lymphocytosis). Acute inflammation from tissue damage, like that caused by a burn, injury, or recent surgery, also prompts the release of these inflammatory cells.
Stress and Medications
The body’s natural stress response can cause a temporary, yet noticeable, elevation in the WBC count. Severe emotional stress, intense physical exertion, or trauma trigger the release of stress hormones, which mobilize leukocytes from the walls of blood vessels into the circulating blood. This phenomenon is a transient physiological change and not necessarily indicative of an underlying disease state.
Certain medications are also known to affect leukocyte production and circulation. Corticosteroids, a common class of anti-inflammatory drugs, are a well-known cause of elevated WBC counts, primarily by increasing circulating neutrophils. Lifestyle factors, such as regular smoking, can also cause a chronic, low-level elevation in the total count due to ongoing inflammatory reaction in the lungs.
Chronic Conditions
Chronic conditions represent another category of causes for a persistent elevation. Autoimmune disorders, such as lupus or rheumatoid arthritis, involve ongoing inflammation that keeps the immune system on alert. Allergies or asthma attacks often lead to an increase in eosinophils as the body attempts to manage the allergic response. Persistent, unexplained elevations are sometimes linked to blood disorders, requiring thorough investigation.
Next Steps and Further Testing
A moderately elevated WBC count requires a discussion with a health provider to contextualize the result within a patient’s overall health picture. Medical history is paramount, including any recent illnesses, current symptoms, and a complete list of medications that could influence the count. A recent cold, a minor injury, or even a stressful day prior to the blood draw may offer a simple explanation.
If the cause is not immediately clear, the provider may order a repeat CBC to see if the elevation persists. They might also request a peripheral blood smear, where a lab specialist visually examines the cells under a microscope to check for any unusual cell shapes or immaturity. Specialized tests, such as inflammatory markers like C-reactive protein (CRP) or an erythrocyte sedimentation rate (ESR), may be used to confirm the presence of systemic inflammation. Treatment is always directed toward resolving the underlying condition, such as administering antibiotics for a bacterial infection or adjusting a medication dosage, rather than simply trying to lower the number itself.