Multi-center validation of the Response Biomedical Corporation RAMP NT-proBNP assay with comparison to the Roche Diagnostics GmbH Elecsys proBNP assay.
BACKGROUND
NT-proBNP measurements aid in the evaluation of patients with suspected heart failure (HF) and may facilitate risk stratification in patients with HF and acute coronary syndrome (ACS). Point-of-care (POC) assays may provide more timely results and potentially improve patient outcomes.


METHODS
We evaluated the analytical performance of the Response Biomedical Corporation whole blood RAMP amino-terminal pro-B type natriuretic peptide (NT-proBNP) POC assay compared to the Roche Elecsys proBNP (NT-proBNP) assay.


RESULTS
Intra-day and total imprecision (% CV) ranged from 5.5% to 10.3% at 140, 449 and 1675 ng/L. The lowest concentration that yields a 20% CV was 57 ng/L. The lower limit of detection was 18 ng/L. The upper limit of linearity was validated to 23,428 ng/L with an average recovery of 95%. Correlation by Passing and Bablok regression yielded RAMP=1.01 Elecsys+14.6, r=0.98 (n=540; range of Elecsys values <5 to >35,000). Concordance of RAMP versus Elecsys using cut-offs of 125 ng/L for subjects <75 years and 450 ng/L for subjects > or =75 was 92% (95% CI 89-94%) for a group consisting of 127 apparently healthy individuals and 208 non-healthy subjects without HF, and 99% (95% CI 97-100%) for patients with HF, using the New York Heart Association (NYHA) functional classification. Overall, 80%, 87%, 97% and 100% of the RAMP results and 77%, 85%, 96% and 100% of the Elecsys results were greater than the age appropriate cut-off for NYHA I, II, III or IV groups. For both the RAMP and Elecsys results, the median NT-proBNP value was statistically correlated (increasing) with NYHA I, II, III or IV groups, respectively (p<0.0001), with no significant difference between the two methods.


CONCLUSIONS
The POC Response Biomedical RAMP NT-proBNP assay provides comparable results that measured on the FDA cleared Roche Elecsys central laboratory platform.
Lee-Lewandrowski
Elizabeth
E
Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
Januzzi
James L
JL
Green
Sandy M
SM
Tannous
Bakhos
B
Wu
Alan H B
AH
Smith
Andrew
A
Wong
Alicia
A
Murakami
MaryAnn M
MM
Kaczmarek
Jason
J
Apple
Fred S
FS
Miller
Wayne L
WL
Hartman
Karen
K
Jaffe
Allan S
AS
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001681:Biological Assay / Q000379:methods*; D015415:Biomarkers / Q000032:analysis; D003327:Coronary Disease / Q000097:blood* / Q000175:diagnosis; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D019095:Point-of-Care Systems; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D013997:Time Factors
D015415:Biomarkers; D010446:Peptide Fragments; D011933:Reagent Kits, Diagnostic; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain