Davis's Lab & Diagnostic Tests

B-Type Natriuretic Peptide and Pro-B-Type Natriuretic Peptide


BNP and proBNP.

Common Use:
To assist in diagnosing heart failure (HF).

Plasma collected in a plastic, lavender-top (EDTA) tube.

Normal Findings:
(Method: Chemiluminescent immunoassay for BNP; electrochemiluminescent immunoassay for proBNP)

BNPConventional UnitsSI Units (Conventional Units × 1)
Male & FemaleLess than 100 pg/mLLess than 100 ng/L
proBNP (N-terminal)
0–74 yrLess than 125 pg/mLLess than 125 ng/L
Greater than 75 yrLess than 449 pg/mLLess than 449 ng/L
BNP levels are increased in older adults.


The peptides B-type natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) are antagonists of the renin-angiotensin-aldosterone system, which assist in the regulation of electrolytes, fluid balance, and blood pressure. BNP, proBNP, and ANP are useful markers in the diagnosis of heart failure HF. BNP, first isolated in the brain of pigs, is a neurohormone synthesized primarily in the ventricles of the human heart in response to increases in ventricular pressure and volume. Circulating levels of BNP and proBNP increase in proportion to the severity of heart failure. A rapid BNP point-of-care immunoassay may be performed, in which a venous blood sample is collected, placed on a strip, and inserted into a device that measures BNP. Results are completed in 10 to 15 min.

This procedure is contraindicated for

Patients receiving nesiritide. Nesiritide (Natrecor) is a recombinant form of BNP that may be given therapeutically by intravenous to patients in acutely decompensated heart failure; with some assays, BNP levels may be transiently and significantly elevated at the time of administration and must be interpreted with caution. The testing laboratory should be consulted to verify whether test measurements are affected by nesiritide.


  • Assist in determining the prognosis and therapy of patients with heart failure.
  • Assist in the diagnosis of heart failure.
  • Assist in differentiating heart failure from pulmonary disease.
  • Cost-effective screen for left ventricular dysfunction; positive findings would point to the need for echocardiography and further assessment.

Potential Diagnosis

Increased In:
BNP is secreted in response to increased hemodynamic load caused by physiological stimuli, as with ventricular stretch or endocrine stimuli from the aldosterone/renin system.

  • Acute kidney injury
  • Cardiac inflammation (myocarditis, cardiac allograft rejection)
  • Chronic kidney disease
  • Cirrhosis
  • Cushing’s syndrome
  • Heart failure
  • Kawasaki’s disease
  • Left ventricular hypertrophy
  • Myocardial infarction
  • Primary hyperaldosteronism
  • Primary pulmonary hypertension
  • Ventricular dysfunction

Decreased In:

Critical Findings


Interfering Factors


Nursing Implications Procedure

Related Studies

Potential Nursing Problems

ProblemSigns & SymptomsInterventions
Gas exchange (related to altered alveolar and capillary exchange secondary to fluid in the alveoli)Decreased activity tolerance; increased shortness of breath with activity; weakness; orthopnea; cyanosis; cough; increased heart rate; weight gain; edema in the lower extremities; weakness; increased respiratory rate; use of respiratory accessory musclesAuscultate and trend breath sounds; perform pulse oximetry to monitor oxygenation; administer oxygen as ordered; collaborate with health-care provider (HCP) to consider intubation and/or mechanical ventilation; place the head of the bed in high Fowler’s position; administer diuretics, vasodilators as ordered; monitor potassium levels
Tissue perfusion (related to compromised cardiac contractility; interrupted blood flow)Hypotension; dizziness; cool extremities; capillary refill greater than 3 sec; weak pedal pulses; altered level of consciousnessMonitor blood pressure; assess for dizziness; check skin temperature for warmth; assess capillary refill; assess pedal pulses; monitor level of consciousness; administer prescribed vasodilators and inotropic drugs
Cardiac output (related to increased preload; increased afterload; impaired cardiac contractility; cardiac muscle disease; altered cardiac conduction)Decreased peripheral pulses; decreased urinary output; cool, clammy skin; tachypnea; dyspnea; edema; altered level of consciousness; abnormal heart sounds; crackles in lungs; decreased activity tolerance; weight gain; fatigue; hypoxiaAssess peripheral pulses and capillary refill; monitor blood pressure and check for orthostatic changes; assess respiratory rate, breath sounds, and orthopnea; assess skin color and temperature; assess level of consciousness; monitor urinary output; use pulse oximetry to monitor oxygenation; monitor sodium and potassium levels; monitor BNP levels; administer ordered angiotensin-converting enzyme (ACE) inhibitors, beta blockers, diuretics, aldosterone antagonists, and vasodilators; provide oxygen administration
Fluid volume (water) (related to altered cardiac output)Overload: Edema; shortness of breath; increased weight; ascites; rales; rhonchi; diluted laboratory values; increased blood pressure; positive jugular venous distention (JVD); orthopnea; cough; restlessness; tachycardia; pulmonary congestion with x-ray; restlessnessDaily weight with monitoring of trends; fluid limit as appropriate; assess for peripheral edema; assess for adventitious lung sounds such as crackles; monitor blood pressure and heart rate; assess for JVD; monitor intake versus output; administer prescribed diuretics; restrict sodium intake; order low sodium diet; monitor laboratory values that reflect alterations in fluid status; manage underlying cause of fluid alteration


  • Positively identify the patient using at least two person-specific identifiers before services, treatments, or procedures are performed.
  • Patient Teaching: Inform the patient this test can assist in diagnosing heart failure.
  • Obtain a history of the patient’s health concerns, symptoms, surgical procedures, and results of previously performed laboratory and diagnostic studies. Include a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a list of the patient’s current medications, including over-the-counter medications and dietary supplements (see Effects of Dietary Supplements online at DavisPlus).
  • Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain to the patient that there may be some discomfort during the venipuncture.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Note that there are no food, fluid, or medication restrictions unless by medical direction.


Potential Complications:

  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection online at DavisPlus. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
  • Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
  • Promptly transport the specimen to the laboratory for processing and analysis.

Post Test

  • Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
  • Treatment Considerations for HF: Recognize anxiety related to test results, and ensure that the patient (if not currently taking) is placed on an ACE inhibitor, β blocker, and diuretic, and is monitored with daily weight measurement. Discuss risk factors. Teach the patient to safely administer ordered oxygen, as appropriate.
  • Nutritional Considerations: Instruct patients to consume a variety of foods within the basic food groups, eat foods high in potassium when taking diuretics, eat a diet high in fiber (25–35 g/day), maintain a healthy weight, be physically active, limit salt intake to 2,000 mg/day, limit alcohol intake, and be a nonsmoker.
  • Nutritional Considerations: Foods high in potassium include fruits such as bananas, strawberries, oranges; cantaloupes; green leafy vegetables such as spinach and broccoli; dried fruits such as dates, prunes, and raisins; legumes such as peas and pinto beans; nuts and whole grains.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Patient Education:

  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
  • Answer any questions or address any concerns voiced by the patient or family.
  • Explain to the patient and family the importance of reporting life-threatening changes such as cool extremities, pallor, and diaphoresis to HCP immediately.
  • Ensure family understands to report any changes in mental status such as confusion.

Expected Patient Outcomes:


  • The patient and family recite the importance of limiting fluids to decrease cardiac stress.
  • The patient and family describe the purpose of taking the prescribed diuretic.

  • The patient and family accurately describe strategies to limit fluid intake and decrease cardiac stress.
  • The patient and family accurately demonstrate how to keep an accurate intake and output.

  • The patient complies with taking all medications as prescribed to support cardiac health.
  • The patient and family adhere to treatment recommendations that can help to prevent a potentially life-threatening situation.

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