White Blood Cell Count

A white blood cell (WBC) count, also known as a leukocyte count, is a medical test that measures the number of white blood cells in a person's blood.

Purpose

The purpose of a WBC count is to:

• Help diagnose infections, inflammatory diseases, and other conditions that affect the immune system
• Monitor the effectiveness of treatment for certain conditions, such as leukemia or lymphoma
• Check for signs of infection in people with weakened immune systems, such as those with HIV/AIDS or undergoing chemotherapy

Procedure

A WBC count is typically performed using a blood sample collected from a vein in the arm. The procedure involves:

• Inserting a needle into a vein to collect a small amount of blood
• Placing the blood sample into a tube that contains an anticoagulant to prevent clotting
• Sending the blood sample to a laboratory for analysis

Types of White Blood Cells

There are five main types of white blood cells, each with different functions:

• Neutrophils: help fight bacterial infections
• Lymphocytes: play a key role in the immune response and help fight viral infections
• Monocytes: mature into macrophages, which help clean up debris and foreign substances
• Eosinophils: involved in allergic reactions and fighting parasitic infections
• Basophils: play a role in inflammatory responses and allergic reactions

Normal Values

The normal range for a WBC count varies depending on the laboratory and the individual's age, but generally falls within the following ranges:

• Adults: 4,500-11,000 cells per microliter (µL)
• Children: 5,000-15,000 cells/µL
• Infants: 6,000-17,000 cells/µL

Abnormal Results

An abnormal WBC count can indicate a range of conditions, including:

• Infections, such as pneumonia or sepsis
• Inflammatory diseases, such as rheumatoid arthritis or lupus
• Leukemia or lymphoma
• Immune system disorders, such as HIV/AIDS

Risks and Limitations

The WBC count is a relatively safe and simple test, but there are some risks and limitations to consider:

• Bleeding or bruising at the needle site
• Infection at the needle site
• False-negative results if the blood sample is not handled properly
• False-positive results if the individual has a condition that affects the WBC count, such as a recent vaccination or medication use

Frequently Asked Questions (FAQs)

What is a white blood cell count?
A test that measures the number of white blood cells in the blood.

Why is a white blood cell count performed?
To diagnose and monitor infections, inflammation, and immune system disorders.

What does a high white blood cell count indicate?
Infection, inflammation, or immune system disorder.

What does a low white blood cell count indicate?
Weakened immune system or bone marrow problem.

How is a white blood cell count performed?
Through a blood sample drawn from a vein.

Is fasting required before the test?
No, usually not required.

Are there any risks associated with the test?
Minimal risk of bleeding or bruising at the needle site.

How long does it usually take to get the results?
Usually within 1-2 days.

What is a normal white blood cell count range?
Typically 4,500 to 11,000 cells per microliter.

Who interprets the test results?
A healthcare provider or doctor.