N-terminal pro B-type natriuretic peptide, STAT

Catalog Number: 05390109160

INTENDED USE

Immunoassay for the in vitro quantitative determination of N-terminal pro-Brain natriuretic peptide in human serum and plasma. This assay is used as an aid in the diagnosis of individuals suspected of having congestive heart failure. The test is further indicated for the risk stratification of patients with acute coronary syndrome and congestive heart failure. The test may also serve as an aid in the assessment of increased risk of cardiovascular events and mortality in patients at risk for heart failure who have stable coronary artery disease.

The electrochemiluminescence immunoassay “ECLIA” is intended for use on the cobas e 601 and cobas e 602 immunoassay analyzers.

STORAGE AND STABILITY

Stability:
unopened at 2-8 °C up to the stated expiration date
after opening at 2-8 °C 12 weeks
on the analyzers 8 weeks

Store at 2-8 °C.

Do not freeze.

Store the Elecsys reagent kit upright in order to ensure complete availability of the microparticles during automatic mixing prior to use.

CALIBRATION

Traceability: This method has been standardized against the proBNP assay ( 03121640). This in turn was standardized against reference standards by weighing pure synthetic NT-proBNP (1-76) into an equine serum matrix.

Every Elecsys reagent set has a barcoded label containing specific information for calibration of the particular reagent lot. The predefined master curve is adapted to the analyzer using the relevant CalSet.

Calibration frequency: Calibration must be performed once per reagent lot using fresh reagent (i.e. not more than 24 hours since the reagent kit was registered on the analyzer). Renewed calibration is recommended as follows:

LIMITS AND RANGES

Measuring range

5.00-35000 pg/mL or 0.600-4130 pmol/L (defined by the Limit of Detection and the maximum of the master curve). Values below the Limit of Detection are reported as < 5.00 pg/mL (< 0.600 pmol/L). Values above the measuring range are reported as > 35000 pg/mL (> 4130 pmol/L) or up to 70000 pg/mL (8277 pmol/L) for 2-fold diluted samples.

Lower limits of measurement

Limit of Detection (LoD) and Limit of Quantitation (LoQ)

Limit of Detection = 5.00 pg/mL (0.600 pmol/L)

Limit of Quantitation = 50.0 pg/mL (5.90 pmol/L)

The Limit of Detection was determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17-A requirements.

The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples. The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).

The Limit of Quantitation (functional sensitivity) is the lowest analyte concentration that can be reproducibly measured with an intermediate precision CV of £ 20 %.

SPECIFIC PERFORMANCE DATA

Representative performance data on the analyzers are given below. Results obtained in individual laboratories may differ.

PRECISION

Precision was determined using Elecsys reagents, pooled human sera and controls in a protocol (EP5-A2) of the CLSI (Clinical and Laboratory Standards Institute): 2 runs per day in duplication each for 21 days (n = 84). The following results were obtained:

b) HS = human serum

c) PC = PreciControl

cobas e 601 and cobas e 602 analyzer
Repeatability Intermediate precision
Sample Mean SD CV SD CV
pg/mL pmol/L pg/mL pmol/L % pg/mL pmol/L %
HSb) 1 59.0 7.00 2.10 0.300 3.50 2.10 0.300 3.50
HS 2 142 16.8 2.90 0.300 2.00 8.60 1.00 2.50
HS 3 522 61.6 7.60 0.900 1.80 8.60 1.00 2.00
HS 4 935 110 17.6 2.10 1.90 23.0 2.70 2.50
HS 5 6552 773 133 15.7 2.00 153 18.0 2.30
HS 6 30870 3643 887 105 2.87 1667 197 5.40
PCc)Cardiac II 1 130 15.3 3.09 0.400 2.40 3.20 0.400 2.50
PC Cardiac II 2 4942 583 108 12.7 2.20 126 15.0 2.60

METHOD COMPARISON

A comparison of the Elecsys proBNP II STAT assay (y) with the Elecsys proBNP II assay (x) using clinical samples gave the following correlations (pg/mL):

Number of samples measured: 120

The sample concentrations were between approximately 5 and 35000 pg/mL.

Passing/Bablok19 Linear regression Deming regression
y = 0.992x - 2.14 y = 0.986x + 14.0 y = 0.988x + 8.83
t = 0.987 r = 0.998 r = 1.00

ANALYTICAL SPECIFICITY

The Elecsys proBNP II STAT assay does not show any significant cross reactions with the following substances, tested with NT-proBNP concentrations of approx. 230 pg/mL and 2300 pg/mL (max. tested concentration):

Adrenomedullin (1.0 ng/mL), aldosterone (0.6 ng/mL), angiotensin I (0.6 ng/mL), angiotensin II (0.6 ng/mL), angiotensin III (1.0 ng/mL), ANP28 (3.1 µg/mL), Arg-vasopressin (1.0 ng/mL), BNP32 (3.5 µg/mL), CNP22 (2.2 µg/mL), endothelin (20 pg/mL), NT-proANP1-30 (preproANP26-55) (3.5 µg/mL), NT-proANP31-67 (preproANP56-92) (1.0 ng/mL), NT-proANP79-98 (preproANP104-123) (1.0 ng/mL), renin (50 ng/mL), urodilatin (3.5 µg/mL).