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White Blood Cell Count (Manual Differential)

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

This test measures the types and proportions of white blood cells in your blood, done manually for detailed analysis. It helps identify infections, immune responses, or other blood disorders.

Quick summary

["Understanding your white blood cell types can reveal clues about health or illness."]

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

Key facts at a glance

LOINC
100849-9
Short code
WBC # Amn Manual
Synonyms
WBC # Amn Manual
Category
chemistry
Sample
fluid
Container
Sterile tube
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
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order this test to diagnose or monitor conditions like infections (e.g., bacterial or viral), autoimmune diseases, or blood disorders. It’s also used before treatments that affect the immune system, such as chemotherapy.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein for a blood draw. If you’re nervous, let your healthcare provider know—they can help make it more comfortable.

What the Results Mean

The manual differential breaks down white blood cells into categories (e.g., neutrophils, lymphocytes, eosinophils) and shows their relative counts. Abnormal results may signal infections, allergies, or other health issues.

Common Conditions Linked to Abnormal Results

High or low counts of certain white blood cells can indicate problems like severe infections, chronic diseases, or reactions to medications. For example, high neutrophils might point to bacterial infections, while low lymphocytes could suggest immune suppression.

Reference range

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

Specimen: fluid

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 Count)

Frequently asked questions

What does a manual WBC differential differ from an automated one?
A manual differential requires a trained technician to count and classify each white blood cell under a microscope, offering more precision for rare or unusual cell types. Automated tests use technology but may miss subtle variations.
How often should I get this test?
Your doctor will determine frequency based on your health needs. Regular checks may be needed if you have chronic conditions or undergo treatments that affect your immune system.
Can diet or stress affect my WBC differential?
Diet and stress can indirectly influence white blood cell activity, but they don’t directly alter the manual differential count. Focus on hydration and rest to support overall blood health.
  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