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Brain natriuretic peptide (B-type) concentration in serum/plasma

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

This test measures the level of brain natriuretic peptide (BNP), a protein produced by your heart’s ventricles in response to increased pressure or volume overload.

Quick summary

["BNP helps assess heart strain and fluid overload in conditions like heart failure."]

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

Key facts at a glance

LOINC
43772-3
Short code
MR Brain+IAC
Synonyms
MR Brain+IAC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
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 BNP Used For?

BNP is primarily used to diagnose or monitor heart failure, evaluate symptoms like shortness of breath or fatigue, and guide treatment decisions. It can also help distinguish between heart-related and other causes of fluid retention.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay method to measure BNP levels.

What Does a High or Low BNP Level Mean?

Elevated BNP levels often indicate heart strain or fluid overload, supporting a diagnosis of heart failure. Lower-than-expected levels may suggest conditions like severe dehydration or certain heart valve disorders.

Common Conditions Monitored with BNP

BNP is commonly used to monitor heart failure, acute decompensated heart failure, and conditions like pulmonary edema. It may also help assess patients with suspected heart-related symptoms but unclear diagnoses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

BNP (Serum/Plasma)

Frequently asked questions

Why might my doctor order a BNP test?
Your doctor may recommend a BNP test if you have symptoms like persistent shortness of breath, swelling, fatigue, or rapid weight gain—especially if these are linked to heart issues. It may also be used to evaluate people with known heart conditions or those with unclear diagnoses.
What are the typical results or reference ranges?
There’s no single reference range for BNP because levels vary by age, health status, and medical conditions. Your results will be compared to your specific clinical picture and symptoms, not a fixed number.
Can BNP levels change with diet or exercise?
BNP levels are primarily influenced by heart function and fluid balance. While diet and exercise can affect overall heart health, they don’t directly alter BNP measurements. Your doctor will consider these factors when interpreting your results.
  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