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White Blood Cell Count with Differential (Serum/Plasma Electrophoresis Profile)

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

This test measures the types and proportions of white blood cells in your blood, often done through a blood sample to assess immune function and identify potential infections or disorders.

Quick summary

["Understanding your white blood cell types helps diagnose health issues and guide treatment plans."]

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

Key facts at a glance

LOINC
26465-5
Short code
WBC # CSF
Synonyms
WBC # CSF
Category
chemistry
Sample
csf
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
CPT
85004
SNOMED
900000000000003002
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order a white blood cell differential when you have symptoms like frequent infections, unexplained fevers, fatigue, or signs of an immune system disorder. It can also be part of routine blood work for monitoring chronic conditions like cancer or autoimmune diseases.

How the Test Works

A small blood sample is taken, often from your arm. The blood is then analyzed to count and identify the five main types of white blood cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. This process may involve techniques like staining and microscopic examination.

Common Conditions Monitored

Changes in white blood cell counts or proportions can signal infections, allergies, inflammatory diseases, or blood disorders. For example, high neutrophil counts may indicate bacterial infections, while low lymphocyte counts could suggest immune deficiencies.

What to Expect Before the Test

No special preparation is usually needed, but inform your doctor about any medications you’re taking, especially blood thinners or steroids, as they may affect results.

Reference range

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

Specimen: csf

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 Profile

Frequently asked questions

What does a white blood cell differential tell me about my health?
It provides detailed information about the types and numbers of white blood cells in your blood. This can help identify whether your immune system is overreacting (e.g., allergies or infections), underactive (e.g., immune deficiencies), or responding to conditions like cancer or inflammation.
Can I eat or drink before this test?
Typically, no special diet or fasting is required for this test. However, always follow your doctor’s instructions, especially if they’ve asked you to avoid certain foods or medications that might affect blood test results.
How long will it take to get my results?
Results are usually available within a few days to a week, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
  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