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Granulocyte Count (Manual Differential)

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

This test measures the percentage of different types of white blood cells called granulocytes in your blood. Granulocytes include neutrophils, eosinophils, and basophils.

Quick summary

["Understanding your granulocyte breakdown helps doctors assess immune function and inflammation."]

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

Key facts at a glance

LOINC
71627-4
Short code
Granulocytes NFr.DF Prt Manual
Synonyms
Granulocytes NFr.DF Prt Manual
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
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 Is Done

Doctors may order a granulocyte differential count to diagnose or monitor conditions affecting white blood cells, such as infections, immune disorders, or blood disorders. It can also help evaluate responses to treatments.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a blood sample. The test is quick and usually painless.

How the Test Works

Blood is examined under a microscope by a trained technician to count and classify granulocytes. Manual methods involve visual inspection rather than automated machines.

Possible Results and Interpretation

Results show the proportion of each granulocyte type (e.g., neutrophils, eosinophils). Abnormal counts may indicate infections, allergies, or other health issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Granulocyte differentials can help identify causes of symptoms like fatigue, fever, or unexplained infections. High eosinophil counts may suggest allergies or parasitic infections, while low neutrophil counts could signal immune suppression or bone marrow disorders.

Short name

Granulocyte Differential Count

Frequently asked questions

What causes granulocyte counts to change?
Changes in granulocyte counts can result from infections (like bacterial or viral), inflammatory conditions, autoimmune diseases, or certain medications. Stress, diet, or even sleep can also temporarily affect white blood cell counts.
Is this test painful?
Most people experience only mild discomfort or a slight sting during blood drawing. The area may feel sore briefly afterward, but this usually goes away quickly.
Can I eat or drink before this test?
You can eat and drink normally before this test unless your doctor specifies otherwise. No fasting is required.
  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