Neutrophil count in serum/plasma (absolute)
This test measures the number of neutrophils, a type of white blood cell, in your blood serum or plasma. Neutrophils help fight infections and inflammation.
["Neutrophils protect your body from infections and help reduce swelling."]
Key facts at a glance
- LOINC
- 93866-2
- Short code
- C4NEF
- Synonyms
- C4 NeF SerPl Ql
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST, tiger top) or red-top tube for serum collection; EDTA plasma tube (lavender top) for plasma collection
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Enzyme-Linked Immunosorbent Assay (ELISA) or Hemolytic Assay (C3 Nephritic Factor detection)
- CPT
- 86161
- SNOMED
- 121800002
- Specimen volume
- 1-2 mL of serum or plasma; minimum 0.5 mL
- Stability
- Serum/plasma stable for 8 hours at room temperature (20-25°C); 2 days refrigerated at 2-8°C; up to 3 months frozen at -20°C or below. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 48–168 hours
- Order
- routine
What Is a Neutrophil Count Used For?
Doctors may order this test to check for infections, inflammation, or conditions like leukemia, where the number of neutrophils might be too high or too low. It can also help monitor treatments for blood disorders or autoimmune diseases.
When Might You Need This Test?
You might need this test if you have symptoms like frequent infections, unexplained fevers, swollen lymph nodes, or if your doctor suspects a blood disorder. It’s also used during chemotherapy or other treatments that affect white blood cell counts.
What to Expect Before the Test
No special preparation is usually needed, but your doctor may ask you to avoid certain medications or activities for a short time. The test is typically done by drawing blood from a vein in your arm.
What Happens During the Test?
A healthcare professional will insert a small needle into your arm to draw blood into a test tube. The process usually takes a few minutes, and you may feel a slight pinch or discomfort.
Reference range
Negative: C4 nephritic factor not detected. Positive: C4 nephritic factor detected, suggestive of complement dysregulation.N/A
No special patient preparation is required. However, patients should be well-hydrated. Inform the laboratory of any current immunosuppressive therapy or recent blood transfusions, as these may influence complement levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Absolute Neutrophil Count (Serum/Plasma)
Frequently asked questions
Why might my neutrophil count be checked?
What do abnormal neutrophil counts mean?
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 15, 2026. · Read our editorial policy