White Blood Cell Differential (Manual Count) – Fractional Components
This test measures specific types of white blood cells (WBCs) in your blood, broken down into fractions, using a manual counting method. It helps identify shifts in immune cell populations that may indicate infections, inflammation, or other health conditions.
["Understanding your blood’s immune cell balance can reveal clues about your health or underlying issues."]
Key facts at a glance
- LOINC
- 40535-7
- Short code
- WBC Other NFr DiafP Manual
- Synonyms
- WBC Other NFr DiafP 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 Is Done
Doctors may order this test to diagnose or monitor conditions like infections (e.g., bacterial vs. viral), autoimmune diseases, or blood disorders. It can also guide treatment decisions, especially when automated tests show inconclusive results.
What to Expect Before the Test
No special preparation is needed. You’ll have a simple blood draw, usually from your arm. If you’re on blood thinners, let your provider know to avoid excessive bruising.
What the Results Mean
Results show proportions of different WBC types (e.g., neutrophils, lymphocytes, eosinophils). Abnormal fractions may signal conditions like chronic infections, allergies, or immune system dysfunction. Your provider will interpret these with your full clinical picture.
Common Conditions Linked to Abnormal Results
High or low fractions of certain cells may point to infections (e.g., high neutrophils for bacterial infections), immune disorders (e.g., low lymphocytes), or chronic conditions like leukemia or rheumatoid arthritis.
Reference range
Adult: 4.5-11.0 x 10^9/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical significance: This test provides detailed immune cell profiling, complementing broader WBC counts. It’s particularly useful for diagnosing conditions where automated differentials are unreliable or for evaluating immune responses to treatment.
Short name
WBC Differential Components (Manual)
Frequently asked questions
What does a manual WBC differential tell me about my immune system?
How long does it take to get results from this test?
Can I eat or drink before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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