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Neutrophil count in bronchoalveolar lavage fluid (neutrophils in BAL fluid)

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

This test measures the proportion of neutrophils, a type of white blood cell, found in the airways after a bronchoalveolar lavage (BAL) procedure. It helps assess inflammation or infection in the lungs.

Quick summary

["Neutrophils in BAL fluid can signal lung inflammation or infection, guiding treatment decisions."]

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

Key facts at a glance

LOINC
56770-1
Short code
Neutrophils NFr Bronch FC
Synonyms
Neutrophils NFr Bronch FC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
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

What Is a Bronchoalveolar Lavage (BAL)?

A BAL is a procedure where a thin tube is inserted through your throat into your lungs to collect a small sample of fluid from the air sacs. This fluid is then analyzed for cells, including neutrophils, to check for lung inflammation or infection.

Why Is This Test Done?

Doctors may order this test if you have symptoms like persistent cough, shortness of breath, or unexplained lung problems. It helps identify causes like pneumonia, lung infections, or inflammatory conditions.

What Does a High Neutrophil Count Mean?

A high neutrophil percentage in BAL fluid often suggests active inflammation or infection in the lungs, such as severe pneumonia, acute respiratory distress syndrome (ARDS), or certain lung diseases.

What Does a Low Neutrophil Count Mean?

A low neutrophil count in BAL fluid may indicate less inflammation or infection, but it can also be normal depending on the clinical context. Other factors, like underlying lung conditions, may influence results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Neutrophils in BAL Fluid

Short name

BAL Neutrophil Percentage

Frequently asked questions

Why might my doctor want to know my neutrophil count in BAL fluid?
Your doctor may use this test to diagnose or monitor lung conditions like severe infections, inflammatory diseases, or conditions affecting lung function. It helps guide treatment, such as antibiotics or anti-inflammatory medications.
How is this test different from a routine blood test?
Unlike routine blood tests (e.g., complete blood count), this test specifically looks at neutrophils in the airways after a BAL procedure. It provides detailed information about lung inflammation or infection that blood tests alone may miss.
What should I expect during or after the BAL procedure?
During the procedure, you may feel mild discomfort but no pain. Afterward, you might experience mild coughing or shortness of breath. Follow-up care depends on your symptoms and doctor’s instructions.
  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