Information about a laboratory test

Low White Blood Cell Count (WBC): What Does It Mean?

A low WBC count, or leukopenia, can occur with some infections, medicines, chemotherapy, or conditions that affect the bone marrow.

Test summary

Test name
White Blood Cell Count (WBC)
Abbreviations
WBC, Lökosit
Category
Hematology / Immunology
Panel
Complete Blood Count (CBC) / Hemogram
Specimen
Whole blood
Common units
/µL, x10^9/L

What does the test measure?

Measures the total number of white blood cells in the blood.

Why is the test ordered?

Used as part of the complete blood count when evaluating infection, inflammation, immune-system conditions, and disorders that affect the bone marrow.

Information about a low result

A low WBC count, or leukopenia, can occur with some infections, medicines, chemotherapy, or conditions that affect the bone marrow.

Information about a high result

A high WBC count, or leukocytosis, can occur with infection, inflammation, stress, certain medicines, and some hematologic conditions.

Reference and clinical context

Use the reference interval printed on your own laboratory report first. Reference intervals may vary by laboratory, method, unit, age, sex, pregnancy, specimen, and other conditions. Numeric records in this workbook are explicitly labeled as either source-based example reference intervals or clinical decision cutoffs.

Reference range 1

>= 4500 – <= 11000 cells/µL

Population
General
Specimen
Whole blood

Example reference interval

MedlinePlus example. Age-specific and lab-specific ranges may differ.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

The neutrophil count can be especially important when considering infection risk. With a low WBC result, the differential count, medicines, and clinical history should be reviewed together.

Related specialties

  • Internal Medicine
  • Hematology
  • Infectious Diseases
  • Pediatrics

Frequently asked questions

Sources

  1. CBC blood test — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2024 · CBC components; example adult reference ranges; high/low RBC, WBC and platelet context · Verified: Aug 11, 2026

  2. White Blood Count (WBC) — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2024 · Total WBC count and relationship to differential · Verified: Aug 11, 2026

  3. Blood Differential — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2024 · Neutrophil, lymphocyte, monocyte, eosinophil, basophil roles and example percentages · Verified: Aug 11, 2026