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Serum/Plasma CD14 Fluorescence Immunoassay (Quantitative) for Neutrophil Count

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

This test measures a protein (CD14) on white blood cells to help assess immune cell activity, often linked to inflammation or infection.

Quick summary

["CD14 helps identify immune responses and potential infections."]

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

Key facts at a glance

LOINC
90736-0
Short code
PNH-MONO
Synonyms
CD14-FLAER- cells/CD33 NFr Bld
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA) or sodium heparin tube specifically designated for flow cytometry; acid-citrate-dextrose (ACD) tubes are also acceptable
Units
N/A
Ref low
98
Ref high
100
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
Flow cytometry using fluorescent aerolysin (FLAER) and fluorochrome-conjugated monoclonal antibodies against CD14 and CD33 surface markers. Cells are analyzed on a flow cytometer to detect the absence of GPI-anchored proteins on monocyte populations, which is characteristic of paroxysmal nocturnal hemoglobinuria (PNH).
CPT
86356
SNOMED
395124008
Specimen volume
3-5 mL of whole blood for adults; minimum 1 mL for pediatric patients
Stability
Specimen must be processed within 24-48 hours of collection when stored at room temperature (18-25°C). Refrigeration may cause loss of cell viability and FLAER binding. Samples older than 48 hours are generally rejected.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
24–72 hours
Order
routine

What Does This Test Measure?

CD14 is a protein found on the surface of certain white blood cells, including neutrophils—a key type of immune cell. This test detects its presence in your blood to evaluate immune function, inflammation, or infection risk. Neutrophils are critical for fighting bacterial infections, and elevated levels may indicate an active immune response.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fever, persistent infections, or signs of chronic inflammation. It can also be part of broader evaluations for conditions like sepsis, autoimmune diseases, or certain cancers.

How Is the Test Performed?

A blood sample is drawn from a vein, typically in your arm. The sample is then tested using a fluorescence-based method to measure CD14 levels. Results are compared to general reference ranges for healthy individuals.

What Do the Results Mean?

Results may show elevated, normal, or reduced CD14 levels, depending on your health status. Elevated levels could signal inflammation or infection, while lower levels might suggest immune system dysfunction or certain blood disorders.

Reference range

Normal: >98% of CD14+/CD33+ monocytes express GPI-anchored proteins (CD14+CD33+FLAER+). PNH clone size reported as percentage of abnormal (CD14+CD33+FLAER-) monocytes. Reference range varies by laboratory; typically PNH clone <1% considered negative, 1-5% borderline, >5% positive.N/A

Specimen: whole-blood

No special patient preparation required. Recent transfusion does not significantly affect results due to short lifespan of donor monocytes. However, recent rituximab or other monoclonal antibody therapy should be disclosed to the laboratory as it may interfere with antibody-based detection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD14 Neutrophil Marker Test (Screening)

Frequently asked questions

What causes abnormal CD14 levels?
Abnormal CD14 levels can result from infections (bacterial or viral), autoimmune diseases, chronic inflammation, or certain blood disorders. Your provider will consider your symptoms and medical history to interpret results.
Is this test painful?
The blood draw itself may cause mild discomfort or bruising, but the test itself is painless. Most people experience only minor soreness afterward.
How soon will I get my results?
Results are typically available within 1–3 business days, depending on lab processing times. Your provider will discuss them 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