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White Blood Cell Differential (Manual Count)

Published: August 9, 2026Updated: August 16, 2026

This test measures the types and proportions of white blood cells in your blood, counted manually by a trained technician.

Quick summary

["Helps identify infections, immune responses, or blood disorders by examining cell types."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
68428-2
Short code
WBC Other # Pcar Manual
Synonyms
WBC Other # Pcar Manual
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
CPT
85004
SNOMED
900000000000003002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

White blood cells (WBCs) fight infections and help your body heal. This test checks if your immune system is responding normally or if certain cell types are unusually high or low, which can signal health issues like infections, allergies, or blood disorders.

How the Test Works

A small blood sample is taken, and a technician examines the cells under a microscope. They count and categorize each type of white blood cell (neutrophils, lymphocytes, monocytes, eosinophils, basophils) to determine their relative amounts.

Common Reasons for Testing

Doctors may order this test to diagnose or monitor conditions such as infections, autoimmune diseases, leukemia, or other blood-related disorders. It’s also used to check immune function before treatments like chemotherapy or organ transplants.

Preparation

No special preparation is needed. You may have a small needle inserted into your arm or hand to draw blood. If you’re nervous, let your healthcare provider know so they can help.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

WBC Differential (Manual)

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your doctor will discuss the findings with you during your follow-up visit.
What does each cell type represent?
Neutrophils: First responders to infections. High levels often mean bacterial infections; low levels may indicate immune problems. Lymphocytes: Key players in fighting viruses and long-term immune responses. Monocytes: Long-lived cells that help fight chronic infections. Eosinophils: Linked to allergies or parasitic infections. Basophils: Rarely involved in acute infections but may signal allergic reactions.
Can diet or medications affect this test?
Diet or over-the-counter medications usually don’t affect manual WBC differentials. However, certain medications (like steroids) or recent infections may influence results. Always inform your doctor about all medications you’re taking.
  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 16, 2026. · Read our editorial policy