The NT-proBNP Chemiluminescence ImmunoAssay (CLIA) Test is a chemiluminescence-based immunoassay for the quantitative detection of NT-proBNP in human serum, plasma (lithium heparin, EDTA), or whole blood using the ALTA CLIAlyzer

NT-proBNP is a non-active prohormone that is released in response to changes in pressure inside the heart. Cardiomyocytes synthesize a pre-propeptide with 134 amino acids (preproBNP), which is split into a signal peptide and a propeptide (proBNP, with 108 amino acids). During secretion from the cardiomyocytes, proBNP is split in a ratio of 1:1 into the physiologically active C-terminal fragment BNP (with 32 amino acids) and the biologically inactive N-terminal fragment NT-proBNP (with 76 amino acids). 70% of physiologic NTproBNP is secreted by the heart ventricles due to their large mass.

Aside from the heart ventricle, NT-proBNP is also secreted by other organs such as the brain, kidney, aorta and adrenal gland, albeit at much lower levels. NT-proBNP was advocated as a beneficial biomarker for evaluating heart failure by the American Association for Clinical Chemistry in 2007 and is allowed to be used for diagnosis and evaluation of heart failure and acute coronary syndrome by the USFDA. There is also evidence suggesting that NT-proBNP has prognostic value in evaluating the increased risk of cardiovascular disease and the mortality of stable coronary artery disease.

The NT-proBNP FIA Test was developed to detect circulating NT-proBNP in serum, plasma or whole blood.

  • Individual ready-to-use cartridges
  • Combines the sandwich immunoassay technique with enzyme-catalyzed chemiluminescence detection
  • Sample volume: 75 μL


Working range: 15 – 35000 pg/mL

Detection Limits

Limit of Blank (LOB): ≤ 10 pg/mL


Intra-lot Precision

CV less than 8%

Inter-lot Precision

CV less than 10%


Linearity between 15 and 35000 pg/mL

Analytical Specificity

The following proteins were tested and found to have an insignificant effect on the measured NT-proBNP.

SubstanceConcentrationCross reactivity
Angiotensin I600 pg/mL≤ 10 pg/mL
Angiotensin II600 pg/mL≤ 10 pg/mL
Angiotensin III1000 pg/mL≤ 10 pg/mL
ANP3.1 mg/mL≤ 10 pg/mL
CNP2.2 mg/mL≤ 10 pg/mL
Aldosterone0.6 ng/mL≤ 10 pg/mL
Renin50 ng/mL≤ 10 pg/mL
Adrenomedullin1 ng/mL≤ 10 pg/mL
Endothelin20 pg/mL≤ 10 pg/mL


No significant interference was detected up to the concentrations mentioned below:

Hemoglobin1000 mg/dL
Bilirubin50 mg/dL
Triglyceride1500 mg/dL
Total Protein10 g/dL
Rheumatoid Factor1500 IU/mL

HAMA Interference

Patient specimens containing human anti-mouse antibodies (HAMA) may give falsely elevated or decreased values.  Although HAMA-neutralizing agents are added, extremely high HAMA serum concentrations may occasionally affect the results.

Hook effect

There is no high-dose hook effect at BNP concentration up to 300000 pg/mL.

Reagents and materials provided

  1. 19-well BNP reagent cartridge
    1. Sample well (1st well)
    2. Reading well for chemiluminescent signal (19th well)
    3. Foil-sealed wells (2nd to 18th wells) comprised of a barcode indicating reagent assay information, the reagent lot number and the expiration date
  2. 3 Calibrators lyophilized powder with NT-proBNP antigen at:
    1. 0 pg/mL
    2. 125 pg/mL
    3. 2500 pg/mL
  3. Registration card
  4. Calibrator card
  5. Instructions for Use

Materials may be required and not provided

  1. Commercial controls

Materials required but not provided

  1. Pipette with disposable tip to dispense up to 100 μL.
  2. For other specific materials and disposables, refer to CLIAlyzer user manual
  3. CLIAlyzer instrument
  4. Powderless gloves
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