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Test Code BNP B-Type Natriuretic Peptide (BNP)

Important Note

Glass tubes are unacceptable for testing.

Additional Codes

Epic: LAB106

Specimen Required

Specimen Type: Plasma

Collection Container/Type: Lavedner top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: 3 mL

Collection Instructions: 

  1. Collect sample and immediately refrigerated or place on wet ice.
  2. Transport sample refrigerated (on wet ice) or centrifuge and freeze plasma as soon as possible.

Specimen Minimum Volume

0.25 mL

Specimen Stability

Plasma

Room temperature: 4 hours

Refrigerated: 24 hours

Frozen: 3 months

 

Whole Blood

Room temperature: 4 hours

Refrigerated: 24 hours

Frozen: Unacceptable

Clinical Significance

B-type natriuretic peptide (brain natriuretic peptide; BNP) is a 32-amino acid-ringed peptide secreted by the heart to regulate blood pressure and fluid balance.(1) BNP is stored in and secreted predominantly from membrane granules in the heart ventricles, and is continuously released from the heart in response to both ventricle volume expansion and pressure overload.(2)

 

The natriuretic peptide system and the renin-angiotensin system counteract each other in arterial pressure regulation. When arterial pressure decreases, the kidneys release renin, which activates angiotensinogen resulting in increased peripheral resistance of the arterioles, thus increasing arterial pressure.

 

The natriuretic peptides counteract the effects of renin secretion, causing a reduction of blood pressure and in extracellular fluid volume.(3) Both BNP and atrial natriuretic peptide (ANP) are activated by atrial and ventricular distension due to increased intracardiac pressure. These peptides have both natriuretic and diuretic properties: they raise sodium and water excretion by increasing the glomerular filtration rate and inhibiting sodium reabsorption by the kidney.

 

The New York Heart Association (NYHA) developed a functional classification system for congestive heart failure (CHF) consisting of 4 stages based on the severity of the symptoms. Various studies have demonstrated that circulating BNP concentrations increase with the severity of CHF based on the NYHA classification.(4-6)

Reference Range

0 - 100 pg/mL

Rejection Due To

Unlabeled, mislabeled, wrong tube type, severely hemolyzed, QNS.

Day(s) and Time(s) Performed

Daily

Report Available

Same day

Method Name

Chemiluminescent Microparticle Immunoassay (CMIA).

LOINC

30934-4

Limitations

1.  EDTA plasma, collected in plastic tubes, should be used for this assay.  The use of glass collection tubes, or other sample types, such as serum or plasma with other anticoagulants, is NOT recommended.

2.  For diagnostic purposes, the ARCHITECT BNP results should be used in conjunction with other clinical data; e.g., symptoms, medical history, etc.  If BNP results are not consistent with other clinical observations, additional information may be required for diagnosis.

3.  Specimens from patients who have received preparations of mouse monoclonal antibodies for diagnosis or therapy may contain human anti-mouse antibodies (HAMA).  Such specimens may show either falsely elevated or depressed values when tested with assay kits which employ mouse monoclonal antibodies.  ARCHITECT BNP reagents contain a component that reduces the effect of HAMA reactive specimens.  Additional clinical or diagnosis information may be required to determine patient status.

4.  Heterophilic antibodies in human plasma can react with reagent immunoglobulins, interfering with in vitro immunoassays.  The presence of heterophilic antibodies in a patient may cause anomalous values to be observed.

5.  ARCHITECT BNP results should not be used interchangeably with other manufacturers' methods for BNP or NT-proBNP determinations.

6.  Measurements of BNP should occur prior to Nesiritide (Natrecor), recombinant BNP treatment and 2 hours post-treatment.