Multicentre evaluation of a second generation point-of-care assay with an extended range for the determination of N-terminal pro-brain natriuretic peptide.
BACKGROUND
In the second generation of the point-of-care (POC) assay Roche CARDIAC proBNP, the upper limit of the measuring range was extended from 3000 to 9000 ng/L.


METHODS
A thirteen-site multicentre evaluation was carried out to assess the analytical performance of the POC NT-proBNP assay and to compare it with a laboratory N-terminal pro-brain natriuretic peptide (NT-proBNP) assay.


RESULTS
In method comparisons of six lots of POC NT-proBNP with the lab reference method (Elecsys proBNP) mean bias ranged from -10 to +17%. In lot-to-lot comparisons all six investigated lots of POC NT-proBNP showed excellent agreement, with mean bias between -7% and +2%. The majority of all coefficients of variation obtained from ten-fold measurements using 56 native blood samples were below 8%. No interference was observed with hemolytic blood (hemoglobin concentrations up to 0.12 mmol/L), lipemic blood (triglyceride concentrations up to 14.0 mmol/L) nor icteric blood (bilirubin concentrations up to 63 micromol/L). Hematocrit values between 24% and 51% had no influence on the assay result. High NT-proBNP concentrations above the measuring range of POC NT-proBNP did not lead to false low results due to potential high-dose hook effect. Results with POC NT-proBNP were not influenced by different ambient temperatures (18 degrees C to 32 degrees C), the sample material used, nor by over- or underdosing by 15 microL compared to the regular sample volume of 150 microL.


CONCLUSIONS
The POC NT-proBNP assay showed an excellent analytical performance including a good agreement with the laboratory method. The assay is therefore suitable for its intended use in point-of-care settings.
Department of Clinical Biochemistry, Viborg Regional Hospital, Viborg, Denmark.
Bo
B
Jørgensen
Thomas
T
Bertsch
Hans-Joachim
HJ
Bröker
Markus
M
Schäfer
Jean-Paul
JP
Chapelle
Romy
R
Gadisseur
Martin R
MR
Cowie
Bert
B
Dikkeschei
Eberhard
E
Gurr
Wiebke
W
Hayen
Gerd
G
Hafner
Yuriko
Y
Stiegler
Hans-Robert
HR
Schönherr
Ruth H
RH
Strasser
Britta
B
Weidtmann
Henning
H
Folkerts
Christian
C
Zugck
Kerstin
K
Hofmann
Rainer
R
Zerback
D009320:Atrial Natriuretic Factor / Q000097:blood*; D003935:Diagnostic Techniques, Cardiovascular / Q000295:instrumentation* / Q000592:standards; D006801:Humans; D019095:Point-of-Care Systems / Q000592:standards; D011498:Protein Precursors / Q000097:blood*; D011786:Quality Control; D015203:Reproducibility of Results; D013696:Temperature
C099254:N-terminal proatrial natriuretic peptide; D011498:Protein Precursors; D009320:Atrial Natriuretic Factor