White Blood Cell Differential with Buffy Coat Analysis
This test examines the types and proportions of white blood cells in your blood, including cells found in the buffy coat layer (a thin layer of cells between red blood cells and plasma). It helps identify infections, immune responses, or blood disorders.
["Understanding your white blood cell types can reveal clues about your health."]
Key facts at a glance
- LOINC
- 92635-2
- Short code
- WBC # Buffy Coat
- Synonyms
- WBC # Buffy Coat
- 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
- 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
A complete blood count (CBC) typically includes a white blood cell differential, but the buffy coat analysis provides a closer look at the cellular components in the thin layer of white blood cells and platelets that separate from red blood cells during blood collection. This can help detect subtle abnormalities in immune cell populations or platelet function.
What the Buffy Coat Represents
The buffy coat contains lymphocytes (B cells, T cells, natural killer cells), monocytes, and sometimes immature or abnormal white blood cells. It also includes platelets. This layer is often examined separately to assess cell morphology and count more precisely than standard CBC methods.
Common Conditions Evaluated
Buffy coat analysis is often used alongside a CBC to diagnose conditions like leukemia, lymphoma, immune deficiencies, or infections where specific white blood cell types are abnormal. It may also help monitor treatment responses in patients with blood disorders.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into a vein (usually in your arm) to draw blood. The test is quick, and you can return to normal activities afterward. If you’re on blood-thinning medication, let your provider know.
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
Short name
WBC Differential (Buffy Coat)
Frequently asked questions
How long does it take to get results from this test?
Can I eat or drink before this test?
Is there any risk or discomfort with 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