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Complete Blood Count with Differential (CBC with Differential)

Published: August 9, 2026Updated: August 17, 2026

This test measures your blood’s overall health, including red blood cells, white blood cells, and platelets, along with the proportions of different types of white blood cells.

Quick summary

["A CBC helps diagnose and monitor conditions like anemia, infections, or blood disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
4514-6
Short code
Comp DAF EntNum RBC
Synonyms
Comp DAF EntNum RBC
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Does a CBC With Differential Measure?

Your blood is analyzed for several key components: Red blood cells (RBCs) help carry oxygen throughout your body. White blood cells (WBCs) fight infections and inflammation. Platelets assist in blood clotting. The differential counts the types of white blood cells—neutrophils, lymphocytes, monocytes, eosinophils, and basophils—to help identify specific health issues.

How Is This Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The sample is then examined under a microscope or processed through an automated analyzer to count and classify cells.

Why Might You Need This Test?

Doctors order a CBC with differential to check for infections, anemia, blood disorders (like leukemia), or other conditions affecting blood cell counts or types.

Common Conditions Monitored or Diagnosed

Results can reveal signs of infections (e.g., high WBCs), anemia (low RBCs), or blood disorders (e.g., abnormal platelet counts). The differential helps pinpoint whether a high WBC count is due to infection, inflammation, or another cause.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CBC with Differential

Frequently asked questions

What does a CBC with differential tell me about my health?
It provides a snapshot of your blood’s cellular composition, helping identify issues like infections, anemia, or blood disorders. For example, very high or low counts of certain white blood cells can signal specific conditions that require medical attention.
How often should I get this test?
Frequency depends on your health status. Routine adults may get a baseline CBC every few years, while those with chronic conditions (e.g., diabetes, heart disease) may need it more often, as directed by their doctor.
Can lifestyle changes affect my CBC results?
Yes—stress, diet, hydration, or recent illness can temporarily alter blood cell counts. For example, dehydration may lower RBC counts, while certain foods (like iron-rich ones) can influence hemoglobin levels. Always discuss any changes with your healthcare provider.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy