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Lung-specific protein antigen (e.g., surfactant protein A or D) in urine

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

This test measures certain proteins found in the lungs, which may appear in urine if there is lung damage or disease.

Quick summary

["This test helps identify lung conditions that might affect urine protein levels."]

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

Key facts at a glance

LOINC
9543-0
Short code
L pneumo1 Ag Ur Ql RIA
Synonyms
L pneumo1 Ag Ur Ql RIA
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ria
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like shortness of breath, persistent cough, or unexplained fluid buildup in the lungs. It can also be used to monitor conditions like pulmonary edema, interstitial lung disease, or infections that affect lung proteins.

What to Expect Before the Test

No special preparation is needed. You’ll provide a urine sample, typically collected in the morning. Avoid strenuous activity or certain medications that might interfere with results for 24 hours before testing.

What the Test Measures

The test detects specific proteins (like surfactant proteins) that are normally found in lung tissue. Elevated levels in urine may suggest lung inflammation, fibrosis, or other lung-related issues.

How the Results Are Interpreted

Results are qualitative (present/absent) rather than numerical. High levels of these proteins in urine may indicate lung damage or disease, prompting further evaluation by your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

None

Frequently asked questions

Will this test show if I have a lung infection?
This test specifically looks for lung proteins in urine, not general infections. If you suspect a lung infection, your doctor may order additional tests like a chest X-ray, sputum culture, or other diagnostic procedures.
Can I take medications before this test?
Avoid medications that might affect urine protein levels (like certain diuretics or NSAIDs) for 24 hours before testing. Always check with your healthcare provider for specific instructions.
What if my urine test is positive for lung proteins?
A positive result may mean your lungs are experiencing stress or damage. Your doctor will discuss next steps, which could include further imaging, lung function tests, or additional blood/urine tests to pinpoint the cause.
  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